Biphenyl ether heterobicyclic platelet activating factor antagonists

ABSTRACT

Compounds of the general formula I; ##STR1## wherein: A 1  is ═N--, ═CH-- or ═CR 1  --; 
     A 2  is --N═, --CH═ or --CR 2  ═; 
     provided that, when one of A 1  and A 2  is a nitrogen atom, the other of A 1  and A 2  is other than a nitrogen atom; 
     wherein the remainder of the variables are defined in the specification; 
     and their pharmaceutically and veterinarily acceptable acid addition salts and hydrates are antagonists of platelet activating factor (PAF) and as such are useful in the treatment or amelioration of various diseases or disorders mediated by PAF.

This is a continuation of application Ser. No. 07/992,269, filed Dec.14, 1992 now U.S. Pat. No. 4,274,094, which is a continuation ofapplication Ser. NO. 07/745,471, filed on Aug. 15, 1991, now U.S. Pat.No. 4,200,412.

This invention relates primarily to novel compounds which are antagonistof platelet activating factor.

Platelet Activating Factor (PAF) is a bioactive phospholipid which hasbeen identified as1-O-hexadecyl/octadecyl-2-acetyl-sn-glyceryl-3-phosphoryl choline. PAFis released directly from cell membranes and mediates a range of potentand specific effects on target cells resulting in a variety ofphysiological responses which include hypotension, thrombocytopenia,bronchoconstriction, circulatory shock, and increased vascularpermeability (oedema/erythema). It is known that these physiologicaleffects occur in many inflammatory and allergic diseases and PAF hasbeen found to be involved in a number of such disorders includingasthma, endotoxin shock, adult respiratory distress syndrome,glomerulonephritis, immune regulation, transplant rejection, gastriculceration, psoriasis, cerebral, myocardial and renal ischemia. Thus thecompounds of the invention, by virtue of their ability to antagonise theactions of PAF, should be of value in the treatment of any of the aboveconditions and any other conditions in which PAF is implicated (e.g.embryo implantation.

Compounds which have been disclosed as possessing activity as PAFantagonists include compounds which are structurally related to the PAFmolecule such as glycerol deriratives (EP-A-0238202), and heterocycliccompounds such as 2,5-diaryl tetrahydrofurans (EP-A-0144804) andimidazopyridine derivatives (EP-A-0260613 and WO-A-8908653).

The present invention provides novel and useful substituted amino acidderivatives and their pharmaceutically acceptable acid addition salts,and pharmaceutical uses thereof as PAF antagonists.

According to a first aspect of the invention there is provided acompound of general formula I; ##STR2## wherein:

A¹ is ═N--, ═CH-- or --CR¹ --;

A² is --N═, --CH═ or --CR² ═;

provided that, when one of A¹ and A² is a nitrogen atom, the other of A¹and A² is other than a nitrogen

R represents hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, halogen or--OC₁ -C₆ alkyl;

each of R¹ and R² independently represents hydrogen, --C₁ -C₆ alkyl,--C₂ -C₆ alkenyl, halogen, --CN, --CO₂ H, --CO₂ C₁ -C₆ alkyl, --CONH₂,--CHO, --CH₂ OH, --CF₃, --OC₁ -C₆ alkyl, --SC₁ -C₆ alkyl, --SOC₁ -C₆alkyl, --SO₂ C₁ -C₆ alkyl, --NH₂, --NHCOMe or --NO₂ or R¹ and R²together with the carbon atoms to which they are attached form a fusedphenyl ring;

R³ represents hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, --C₂ -C₆alkynyl, --OC₁ -C₆ alkyl, --SC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)OC₁ -C₆alkyl, --(C₁ -C₆ alkyl)SC₁ -C₆ alkyl, --CF₃, --(C₁ -C₆ alkyl)phenyl,--C₃ ∝C₈ cycloalkyl, --C₄ -C₈ cycloalkenyl, --(C₁ -C₆ alkyl) C₃ -C₈cycloalkyl, --(C₁ -C₆ alkyl)C₄ -C₈ cycloalkenyl or thiophenyl;

R⁴ represents hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, --C₂ -C₆alkynyl, --CO₂ C₁ -C₆ alkyl, --SC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)SC₁ -C₆alkyl, --(C₁ -C₆ alkyl)OC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)phenyl orthiophenyl;

R⁵ represents hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, --C₂ -C₆alkynyl, --COC₁ -C₆ alkyl, --CO₂ C₁ -C₆ alkyl, --(COC₁ -C₆ alkyl)phenyl,--(CO₂ C₁ -C₆ alkyl) phenyl, --(C₁ -C₆ alkyl) OC₁ -C₆ alkyl, --(C₁ -C₆alkyl) SC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl, --C₃ -C₈cycloalkyl, --C₄ -C₈ cycloalkenyl or a group --D wherein D represents agroup: ##STR3## wherein n is an integer from 0 to 3, and each of R⁸ andR⁹ is independently hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, --C₂ -C₆alkynyl, halogen, --CN, --CO₂ H, --CO₂ C₁ -C₆ alkyl, --CONH₂, --CONHC₁-C₆ alkyl, --CONH (C₁ -C₆ alkyl)₂ ; --CHO, --CH₂ OH, --CF₃, --OC₁ -C₆alkyl, --SC₁ -C₆ alkyl, --SOC₁ -C₆ alkyl, --SO₂ C₁ -C₆ alkyl, --NH₂ or--NHCOMe;

each of R⁶ and R⁷ independently represents hydrogen, halogen, --C₁ -C₆alkyl optionally substituted by one or more halogen atoms, --C₂ -C₆alkenyl, --C₂ -C₆ alkynyl, --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl, --(C₁ -C₆alkyl)SC₁ -C₆ alkyl, --(C_(C) ₆ alkyl)OC₁ -C₆ alkyl, --(C₁ -C₆alkyl)N(C₁ -C₆ alkyl)₂, -C₃ -C₈ cycloalkyl, --C₄ -C₈ cycloalkenyl, --(C₁-C₆ alkyl)C₃ -C₈ cycloalkyl, --(C₁ -C₆ alkyl) C₄ -C₈ cycloalkenyl, --(C₁-C₆ alkyl)OC₃ -C₈ cycloalkyl, --(C₁ -C₆ alkyl)OC₄ -C₈ cycloalkenyl,--(C₁ -C₆ alkyl) SC₃ -C₈ cycloalkyl, --(C₁ -C₆ alkyl)SC.sub. 4 -C₈cycloalkenyl, a side chain of a naturally occurring amino acid, a group--D as defined above or a --(C₁ -C₆ alkyl)OD group wherein D is asdefined above;

or R⁶ together with R⁵ and the atoms to which they are attached form a 5to 8 membered nitrogen-containing heterocyclic ring;

or R⁶ and R⁷ together with the carbon atom to which they are attachedform a C₃ -C₈ cycloalkyl ring;

B represents a) a --ZR¹⁰ group wherein Z is --C(═O)--, --C(═O)O--,--C(═S)-- or: --C(═S)O-- and R¹⁰ is --C₁ -C₁₈ alkyl optionallysubstituted by one or more halogen atoms, --C₂ -C₁₈ alkenyl, --C₂ -C₁₈alkynyl, --(C₁ -C₆ alkyl) OC₁ -C₆ alkyl, --(C₁ -C₆ alkyl) SC₁ -C₆ alkyl,--(C₁ -C₆ alkyl)O(C₁ -C₆ alkyl) OC₁ -C₆ alkyl, --C₃ -C₈ cycloalkyl, --C₄-C₈ cycloalkenyl, pyridyl, a group --D as defined above or a --(C₁ -C₆alkyl)OD group wherein D is as defined above;

b) a --CONR¹¹ R¹² group wherein each of R¹¹ and R¹² is independentlyhydrogen, --C₁ -C₁₈ alkyl optionally substituted by one or more halogenatoms, --C₂ -C₁₈ alkenyl, --C₂ -C₁₈ alkynyl, --C₃ -C₈ cycloalkyl, --C₄-C₈ cycloalkenyl, pyridyl, a group --D as defined above or R¹¹ and R¹²together with the nitrogen atom no which they are attached form a 5 to 8membered nitrogen-containing heterocyclic ring;

or a pharmaceutically or veterinarily acceptable acid addition salt orhydrate thereof.

Hereafter in this specification the term "compound" includes "salt" or"hydrate" unless the context requires otherwise.

As used herein the term "halogen" or its abbreviation "halo" meansfluoro, chloro, bromo or iodo.

As used herein the term "C₁ -C₆ alkyl" refers to straight chain orbranched chain hydrocarbon groups having from one to six carbon atoms.Illustrative of such alkyl groups are methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl and hexyl.

As used herein the term "C₁ -C₁₈ alkyl" refers to straight chain orbranched chain hydrocarbon groups having from one to eighteen carbonatoms. Illustrative of such alkyl groups are methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl,hexyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,heptadecyl, and octadecyl. From the carbon atoms may be preferred.

As used herein the term "C₂ -C₆ alkenyl" refers to straight chain orbranched chain hydrocarbon groups having from two to six carbon atomsand having in addition one double bond, of either E or Z stereochemistrywhere applicable. This term would include for example, vinyl,1-propenyl, 1-- and 2-butenyl and 2-methyl-2-propenyl.

As used herein the term "C₂ -C₁₈ alkenyl" refers to straight chain orbranched chain hydrocarbon groups having from two to eighteen carbonatoms and having in addition one or more double bonds, of either E or Zstereochemistry where applicable. This term would include for example,vinyl, 1-propenyl, 1- and 2-butenyl, 2-methyl-2-propenyl, geranyl, andfarnesyl. From two to six carbon atoms may be preferred.

As used herein the term "C₂ -C₆ alkynyl" refers to straight chain orbranched chain hydrocarbon groups having from two to six carbon atomsand having in addition one triple bond. This term would include forexample, ethynyl, 1-propynyl, 1-- and 2-butynyl, 2-methyl-2-propynyl,2-pentynyl, 3-pentynyl, 4-pentynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl and5-hexynyl.

As used herein the term "C₂ -C₁₈ alkynyl" refers to straight chain orbranched chain hydrocarbon groups having from two to six carbon atomsand having in addition one triple bond. This term would include forexample, ethynyl, 1-propynyl, 1- and 2-butynyl, 2-methyl-2-propynyl,2-pentynyl, 3-pentynyl, 4-pentynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl,5-hexynyl, 10-undecynyl, 4-ethyl-1-octyn-3-yl, 7-dodecynyl, 9-dodecynyl,10-dodecynyl, 3-methyl-1-dodecyn-3-yl, 2-tridecynyl, 11-tridecynyl,3-tetradecynyl, 7-hexadecynyl and 3-octadecynyl. From two to six carbonatoms may be preferred.

As used herein the term "OC₁ -C₆ alkyl" refers to straight chain orbranched chain alkoxy groups having from one to six carbon atoms.Illustrative of such alkoxy groups are methoxy, ethoxy, propoxy,isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy,neopentoxy and hexoxy.

As used herein the term "SC₁ -C₆ alkyl" refers to straight chain orbranched chain alkylthio groups having from one to six carbon atoms.Illustrative of such alkyl groups are methylthio, ethylthio, propylthio,isopropylthio, butylthio, isobutylthio, sec-butylthio, tert-butylthio,pentylthio, neopentylthio and hexylthio.

As used herein, the term "C₃ -C₈ cycloalkyl" refers to an alicyclicgroup having from 3 to 8 carbon atoms. Illustrative of such cycloalkylgroups are cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.

As used herein, the term "C₄ -C₈ cycloalkenyl" refers to an alicyclicgroup having from 4 to 8 carbon atoms and having in addition One or moredouble bonds. Illustrative of such cycloalkenyl groups arecyclopentenyl, cyclohexenyl, cyclohephenyl and cyclooctenyl.

As used herein, the term "naturally occurring amino acid" includesalanine, arginine, asparagine, aspartic acid, cysteine, cystine,glutamic acid, glycine, histidine, 5-hydroxylysine, 4-hydroxyproline,isoleucine, leucine, lysine, methionine, phenylalanine, prolite, serine,threonine, tryptophan, tyrosine, valine, α-aminoadipic acid,α-amino-n-butyric acid, 3,4-dihydroxyphenylalanine, homoserine,α-methylserine, ornithine, pipecolic acid, and thyroxine. The aminoacids may have their side chains protected for example the carboxylgroups of aspartic acid, glutamic acid and α-aminoadipic acid may beesterified (for example as a C₁ -C₆ alkyl ester), the amino groups oflysine, ornithine, 5-hydroxylysine, 4-hydroxyproline may be converted toamides (for example as a COC₁ -C₆ alkyl amide) or carbamates (forexample as a C(═O)0C₁ -C₆ alkyl or C(--O)OCH₂ Ph carbamate), thehydroxyl groups of 5-hydroxylysine, 4-hydroxyproline, serine, threonine,tyrosine, 3,4-dihydroxyphenylalanine, homoserine, α-methylserine andthyroxine may be converted to ethers (for example a C₁ -C₆ alkyl or a(C₁ -C₆ alkyl)phenyl ether) or esters (for example a C(═O)C.sub. 1 -C₆alkyl ester) and the thiol group of cysteine may be converted tothioethers (for example a C₁ -C₆ alkyl thioether) or thioesters (forexample a C(═O)C₁ -C₆ alkyl thioester).

As used herein, the term "nitrogen-containing heterocyclic ring" refersto an aromatic or allcyclic ring comprising one or more nitrogen atomsand optionally one or more other heteroatoms. Illustrative of such ringsare pyrrolidine, piperidine, hexamethyleneimine, heptamethyleneimine,morpholine and piperazine.

In compounds of this invention, the presence of several asymmetriccarbon atoms gives rise to diastereoisomers, each of which consists oftwo enantiomers, with the appropriate R or S stereochemistry at eachchiral centre. The invention is understood to include all suchdiastereoisomers, their optically active enantiomers and mixturesthereof.

The term "pharmaceutically or veterinarily acceptable acid additionsalt" refers to a salt prepared by contacting a compound of formula (I)with an acid whose anion is generally considered suitable for human oranimal consumption.

Examples of pharmaceutically and/or veterinarily acceptable acidaddition salts include the hydrochloride, sulphate, phosphate, acetate,propionate, lactate, maleate, succinate and tartrate salts.

Preferred Compounds include those in which, independently or in anycompatible combination:

A¹ represents ═N--, --CH-- or ═CR¹ --;

A² represents --N═, --CH-- or --CR² --;

R represents a halogen (for example chlorine) atom or a hydrogen atom;

R¹ represents a halogen (for example fluorine) atom or a hydrogen atom;

R² represents a halogen (for example fluorine) atom or a hydrogen atom;

R³ represents a hydrogen atom or a --C₁ -C₆ alkyl (for example methyl,ethyl or n-pentyl) group;

R⁴ represents a hydrogen atom;

R⁵ represents a hydrogen atom, a --C₁ -C₆ alkyl (for example methyl orpropyl) group, a --C₂ -C₆ alkenyl (for example allyl) group, a --COC₁-C₆ alkyl (for example acetyl) group, a --CO₂ C₁ -C₆ alkyl (for exampleethoxycarbonyl) group, or a --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl (forexample methoxycarbonylmethyl, ethoxycarbonylmethyl ort-butoxycarbonylmethyl) group;

R⁶ represents a hydrogen atom, a --C₁ -C₆ alkyl (for example methyl,isopropyl, n-butyl, isobutyl or 2-methylpropyl) group, a --C₂ -C₆alkenyl (for example allyl) group, a --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl(for example ethyl 3-propionate) group, a --(C₁ -C₆ alkyl)SC₁ -C₆ alkyl(for example methylthioethylene) group, the side chain of a naturallyoccurring amino acid, a group --D or a --(C₁ -C₆ alkyl)OD group, or R⁵and R⁶, and the atoms to which they are attached form a 5 to 8 memberednitrogen-containing heterocyclic (for example pyrrolidine) ring;

R⁷ represents a hydrogen atom or a --C₁ -C₆ alkyl (for example methyl)group, or together with R⁶ and the carbon atom to which they areattached forms a C₃ -C₈ cycloalkyl (for example cyclohexyl) ring;

when R⁶ represents the side chain of a naturally occurring amino acidthe preferred stereochemistry of the carbon atom to which R⁶ and R⁷ areattached is the same as that of the naturally occurring amino acid;

n represents an integer of 0 or 1;

R⁸ represents a hydrogen atom or a --OC₁ -C₆ alkyl (for example methoxy)group;

R⁹ represents a hydrogen atom;

Z represents a --C(═O)-- group or a --C(--O)O-- group;

R¹⁰ represents a --C₁ -C₁₈ alkyl (for example methyl, ethyl, n-propyl,isiopropyl, n-butyl, sec-butyl, tert-butyl or octadecyl) group a --C₂-C₁₈ alkenyl (for example allyl) group, a --(C₁ -C₆ alkyl) OC₁ -C₆alkoxy (for example 2-ethoxyethyl, 1-methyl-2-methoxyethyl) group, a--(C₁ -C₆ alkyl)O(C₁ -C₆ alkyl) OC₁ -C₆ alkyl (for example2-(2-ethoxyethoxyethyl) group, a group --D or a --(C₁ -C₆ alkyl)OD (forexample 2-benzoxyethyl) group;

R¹¹ represents a --C₁ -C₆ alkyl (for example methyl) group or a pyridyl(for example 2-pyridyl) group, or together with R¹² and the nitrogenatom to which they are attached forms a 5 to 8 memberednitrogen-containing heterocyclic (for example pyrrolidine or morpholine)ring; and

R¹² represents a hydrogen atom.

Preferred side chains of naturally occurring amino acids include sidechains of alaninc, valine, isoleucine, leucine, phenylalanine, tyrosine,serine, methionine, and aspartic acid.

Particularly preferred compounds include those in which, independentlyor in any compatible combination:

A¹ represents --N═;

A² represents ═CH--;

R represents a halogen (for example chlorine) atom or a hydrogen atom;

R¹ represents a hydrogen atom;

R² represents a hydrogen atom;

R³ represents a --C₁ -C₆ alkyl (for example methyl, ethyl or n-pentyl)group;

R⁴ represents a hydrogen atom;

R⁵ represents a hydrogen atom or a --C₁ -C₆ alkyl (for example methyl orpropyl) group, a --C₂ -C₆ alkenyl (for example allyl) group, a --CO₂ C₁-C₆ alkyl (for example ethoxycarbonyl) group or a --(C₁ -C₆ alkyl)CO₂ C₁-C₆ alkyl (for example methoxycarbonylmethyl, ethoxycarbonylmethyl ort-butoxycarbonylmethyl) group;

R⁶ represents a --C₁ -C₆ alkyl (for example. methyl, isopropyl, n-butyl,isobutyl or 2-methylpropyl) group, a --C₂ -C₆ alkenyl (for exampleallyl) group, a --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl (for example ethyl3-propionate) group, --(C₁ -C₆ alkyl) SC₁ -C₆ alkyl (for examplemethylthioethylene) group or the side chain of a naturally occurringamino acid;

R⁷ represents a hydrogen

when R⁶ represents the side chain of a naturally occurring amino acidthe preferred stereochemistry of the carbon atom to which R⁶ and R⁷ areattached is the same as that of the naturally occurring amino acid;

n represents an integer of 1;

R⁸ represents a hydrogen atom;

R⁹ represents a hydrogen atom;

B represents a --ZR¹⁰ group;

Z represents a --C (═O)O-- group;

R¹⁰ represents a --C₁ -C₁₈ alkyl (for example methyl, ethyl, n-propyl,isopropyl, n-butyl, sec-butyl, tert-butyl or octadecyl) group, a --C₂-C₁₈ alkenyl (for example allyl) group, a --(C₁ -C₆ alkyl) OC₁ -C₆ alkyl(for example 2-ethoxyethyl, 1-methyl-2-methoxyethyl) group, --(C₁ -C₆alkyl)O(C₁ -C₆ alkyl)OC₁ -C₆ alkyl (for example 2-(2-ethoxyethoxyethyl)group, a group --D or a --(C₁ -C₆ alkyl)OD ([or example 2-benzoxyethyl)group.

Particularly preferred side chains of naturally occurring amino acidsinclude side chains of isoleucine, leucine and methionine.

Exemplary Compounds include:

1. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonylglycine methylester,

2.N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2,2-dimethylglycinemethyl ester,

3.N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-1-aminocyclohexanecarboxylicacid methyl ester,

4.N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-2-phenylglycinemethyl ester,

5. N-4- (1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-valine methylester,

6. N-4- (1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-isoleucinemethyl ester,

7. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine methylester,

8. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-D-leucine methylester;

9. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-norleucinemethyl ester,

10. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester,

11.N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-methyl-L-tyrosinemethyl ester,

12.N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-benzyl-L-serinemethyl ester,

13. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-methioninemethyl ester,

14. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine ethylester,

15. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalanineethyl ester,

16. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-methionineethyl ester,

17. N-4- (1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-asparticacid diethyl ester,

18. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucineisopropyl ester,

19. N-4-(1H-2-Methylbenzimidazolyimethyl)phenylsulphonyl-L-leucinen-butyl ester,

20. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-alaninetert-butyl ester,

21. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninetert-butyl ester,

22. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucinebenzyl ester,

23. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninebenzyl ester,

24. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-isoleucinemethylamide,

25. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethylamide,

26. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalanine2-pyridylamide,

27. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemorpholinoamide,

28. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucinepyrrolidinoamide,

29. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-prolinylmethyl ester,

30. N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-prolinylbenzyl ester,

31. (A) N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester,

(B) N-4-( 1H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester,

32. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester,

33. (A)N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester,

(B) N-4-(1H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester,

34. (A)N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-O-benzyl-L-serinemethyl ester,

(B) N-4-(1H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-O-benzyl-L-serine methyl ester,

35. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B) N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester,

36. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-propyl ester,

(B) N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine n-propyl ester,

37. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineallyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineallyl ester,

38. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinei-propyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinei-propyl ester,

39. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester,

40. (A) N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine1-methylpropyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine1-methylpropyl ester,

41. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester,

42. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-ethoxyethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-ethoxyethyl ester,

43. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-benzoxyethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-benzoxyethyl ester,

44. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine1-methyl-2-methoxyethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine1-methyl-2-methoxyethyl ester,

45. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-(2-ethoxyethoxy) ethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-(2-ethoxyethoxy) ethyl ester,

46. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycineethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycineethyl ester,

47. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-methionineethyl ester,

(B)N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-methionineethyl ester,

48. (A)N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester,

(B)N-4-(1H-2-Methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester,

49. (A)N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-4-(1H-2-Methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester,

50.N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane,

51. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane,

(B) N-4-(1H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane,

52.N-Methyl-N-4-(1H-2-methylbenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester,

53. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

54.N-Methyl-N-4-(1H-2-methylbenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester,

55. (A)N-Methyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-Methyl-N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

56. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinei-propyl ester,

(B) N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine i-propylester,

57. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester,

(B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester,

58. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester,

(B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester,

59. (A)N-Allyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-Allyl-N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

60. (A)N-Allyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-allyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

61. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycinemethyl ester,

(B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycinemethyl ester,

62. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycineethyl ester,

(B) N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycineethyl ester,

63. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-isoleucineallyl ester,

(B)N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-isoleucineallyl ester,

64. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemorpholinoamide,

(B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemorpholinoamide,

65.N-Propyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

66. N-Propyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester,

67.N-Propyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

68. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane,

(B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane,

69. (A)N-t-Butoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B) N-t-Butoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester,

70. (A) N-Ethoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester,

(B)N-Ethoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

71. (A)N-Methoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-Methoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

72. (A)N-Methyl-N-3-chloro-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-Methyl-N-3-chloro-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-n-leucineethyl ester,

73. N-Methyl-N-4-(1H-2-ethylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester,

74.N-Methyl-N-4-(1H-2-n-pentylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

75. N-Acetyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester,

76. (A)N-Ethoxycarbonyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

(B)N-Ethoxycarbonyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester,

77.N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineoctadecyl ester.

Compounds of general formula I may be prepared by any suitable methodknown in the art and/or by the following process, which itself formspart of the invention.

According to a second aspect of the invention, there is provided aprocess for preparing a compound of general formula I as defined above,the process comprising:

(a) treating an imidazole derivative represented by general formula II##STR4## wherein A¹, A², R¹, R² and R³ are as defined in general formulaI, with a suitable base (e.g. sodium hydride, potassium hydride, sodiumbis (trimethylsilyl)amide, or potassium hydroxide), followed by acompound of general formula III ##STR5## wherein R, R⁴, R⁵, R⁶, R⁷, andB are as defined in general formula I, and L is chloro, bromo, iodo,methanesulphonyloxy, ptoluenesulphonyloxy ortrifluoromethanesulphonyloxy; or

(b) treating a substituted diamino compound of general formula IV##STR6## wherein A¹, A², R, R¹, R², R⁴, R⁵, R⁶, R⁷, and B are as definedin general formula I, with a carboxylic acid of general formula V

    R.sup.3 CO.sub.2 .sup.H                                    V

wherein R³ is as defined in general formula I, or a suitable derivativethereof; and

(c) optionally after seep (a) or step (b) converting, in one or aplurality of steps, a compound of general formula I into anothercompound of general formula I.

The reaction of step (a) can for preference be conducted in an aproticsolvent (e.g. tetrahydrofuran, N,N-dimethylformamide or acetonitrile) toyield compounds of general formula I. In the case where anunsymmetrically substituted imidazole derivative is used the reactioncan yield an isomeric mixture, which is separated by chromatography toyield compounds of general formula I.

In step (b) derivatives of carboxylic acids of general formula V, whichare suitable substrates for the reaction include acid halides of generalformula VI

    R.sup.3 CO.sub.2 X                                         VI

wherein R³ is as defined in general formula I and X is fluoride,chloride, bromide or iodide, acid anhydrides of general formula VII

    (R.sup.3 CO).sub.2 O                                       VII

wherein R³ is as defined in general formula I, trialkylorthoesters ofgeneral formula VIII ##STR7## wherein R³ is as defined in generalformula I and R¹³ is --C₁ -C₆ alkyl, or imino ether salts of generalformula IX ##STR8## wherein R³ is as defined in general formula I, R¹³is --C₁ -C₆ alkyl and X is fluoride, chloride, bromide, or iodide.Carboxylic acids of general formula V, acid halides of general formulaVI, acid anhydrides of general formula VII, trialkylorthoesters ofgeneral formula VII and imino ether salts of general formula IX areavailable in the art or can be prepared by methods analogous to thoseknown in the art

By means of step (c) compounds of general formula I wherein B is a--CONR11R¹² group wherein R¹¹ and R¹² are as defined for general formulaI, may be prepared by the following methods$

i) by treatment of a compound of general formula I wherein B is a --CO₂R¹⁰ group wherein R¹⁰ is a benzyl group with hydrogen in the presence ofa noble metal catalyst (e.g. 10% palladium on charcoal) to give acarboxylic acid which is then treated with an amine of general formulaHNR¹¹ R¹² in the presence of a coupling reagent (e.g.1,3-dicyclohexylcarbodiimide);

ii) by treatment of a compound of general formula I wherein B is a --CO₂R¹⁰ group wherein R¹⁰ is lower alkyl with a dimethylaluminium amide ofgeneral formula x

    (Me).sub.2 AlNR.sup.11 R.sup.12                            X

wherein R¹¹ and R¹² are as defined in general formula I, which isprepared it situ from trimethylaluminium and an amine of general formulaHNR11R¹².

Also by means of step (c) certain compounds of general formula I whereinB is a --CO₂ R¹⁰ group wherein R¹⁰ is as defined in general formula I,may be prepared by base catalysed hydrolysis to give a compound ofgeneral formula I wherein B is a --CO₂ H group which is subsequentlyesterified with an alcohol of general formula HOR¹⁰ in the presence of acoupling reagent (e.g. 1,3-dicyclohexylcarbodiimide).

Also by means of step (c) certain compounds of general formula I whereinB is a --CO₂ R¹⁰ group wherein R¹⁰ is as defined in general formula I ora CONR¹¹ R¹² group wherein R¹¹ and R¹² are as defined in general formulaI but are not hydrogen atoms, may be prepared by treatment of a compoundof general formula I wherein R⁵ is hydrogen with base followed by anelectrophile of general formula XI

    LR.sup.5                                                   XI

wherein R⁵ is as defined in general formula I but is not a hydrogenatom, a phenyl or a substituted phenyl group, and L is chloro, bromo,iodo, methanesulphonyloxy, p-toluenesulphonyloxy ortrifluoromethanesulphonyloxy. Electrophiles of general formula VII areavailable in the art or can be prepared by procedures known to thoseskilled in the art.

Also by means of step (c) certain compounds of general formula I whereinR⁵ is as defined in general formula I but is not a hydrogen atom, B is a--CO₂ R¹⁰ group wherein R¹⁰ is as defined in general formula I or a--CONR¹¹ R¹² group wherein R¹¹ and R¹² are as defined in general formulaI but are not hydrogen atoms, can be prepared by treatment of a compoundof general formula I wherein R⁴ is a hydrogen atom with a suitable base(e.g. sodium bis(trimethylsilyl)amide) in an aprotic solvent (e.g.tetrahydrofuran) followed by an electrophile of the general formula LR⁴wherein R⁴ is --C₁ -C₆ alkyl, --C₃ -C₆ alkenyl, --C₃ -C₆ alkynyl, --CO₂C₁ -C₆ alkyl, `(C₁ -C₆ alkyl) SC₁ -C₆ alkyl, (C₁ -C₆ alkyl)OC₁ -C₆alkoxy or --(C₁ -C₆ alkyl)phenyl and L is chloro, bromo, iodo,methanesulphonyloxy, p-toluenesulphonyloxy ortrifluoromethanesulphonyloxy or by a C₁ -C₆ alkyl disulphide or phenyldisulphide electrophile. Electrophiles of the general formula LR⁴ anddisulphide electrophiles are available in the art or can be prepared bymethods analogous to those known in the art.

Imidazole derivatives of general formula II may be prepared by a numberof methods. The first method involves treatment of a 1,2-diamine ofgeneral formula XII ##STR9## wherein A¹, A², R¹ and R² are as defined ingeneral formula I, with a carboxylic acid of general formula V, an acidhalide of general formula VI, an acid anhydride of general formula VII,a trialkylorthoester of general formula VIII or an imino ether salt ofgeneral formula IX.

1,2-Diamines of general formula XII are available in the art or may beprepared by the reduction of a 1,2-nitroamine of general formula XIII##STR10## wherein A¹, A², R¹ and R² are as in general formula I, forexample in the presence of hydrogen and a catalyst such as palladium orplatinum.

1,2-Nitroamines of general formula XIII are available in the or can beprepared by methods analogous to those known in the art.

In a second method imidazole derivatives of general formula II may beprepared by the treatment of an 1,2-nitroamide of general formula XIV##STR11## wherein A¹, A² , R¹, R² and R³ are as defined in generalformula I, with a suitable reducing agent (e.g. tin in acetic acid).

1,2-Nitroamides of general formula XIV may be prepared by the treatmentof a 1,2-nitroamine of general formula XIII with an acid chloride ofgeneral formula VI wherein R³ is as defined in general formula I, in anaprotic solvent and in the presence of a suitable base such as, forexample, triethylamine. Alternatively, the reaction may be conductedutilising an acid anhydride of general formula VII Wherein R³ is asdefined in general formula I.

Another procedure for preparing 1,2-nitroamides of general formula XIVinvolves reaction of a 1,2-nitroamine of general formula XIII witha-carboxylic acid of general formula V, wherein R³ is as defined ingeneral formula I, in the presence of a coupling reagent (e.g.1,3-dicyclohexylcarbodiimide).

Compounds of general formula III may be prepared by treatment of anamine of general formula XV ##STR12## wherein R⁵, R⁶, R⁷ and B are asdefined in general formula I, with a sulphonyl halide of general formulaXVI ##STR13## wherein R and R⁴ is as defined in general formula I, L ischloro, bromo, iodo, methanesulphonyloxy, p-toluenesulphonyloxy ortrifluoromethanesulphonyloxy and Hal is a halide (e.g. fluoro, chloro orbromo), in the presence of a suitable base (e.g. triethylamine). Aminesof general formula XV and sulphonyl halides of general formula XVI areknown in the art or may be prepared by methods known in the art.

Substituted 1,2-diamines of general formula IV may be prepared by thereduction of a substituted 1,2-nitroamine of general formula XVII##STR14## wherein A¹, A², R, R¹, R², R⁴, R⁵, R⁶, R⁷, and B are asdefined in general formula I, for example in the presence of hydrogenand a catalyst such as palladium or platinum.

Substituted; 1,2-nitroamines of general formula XVII may be prepared bya number of methods. The first of these methods involves the treatmentof a nitro compound of general formula XVIII ##STR15## wherein A¹, A²,R¹, and R² are as defined in general formula I and G is halo or --OC₁-C₆ alkyl, is treated with an amino compound of general formula XIX##STR16## wherein R, R⁴, R⁵, R⁶, R⁷ and B are as defined in generalformula I. Nitro compounds of general formula XVIII are available in theart or can be prepared by methods analogous to those known in the art.Amino Compounds of general formula XIX can be prepared by treatment of acompound of general formula III with hexamethylenetetramine followed bytreatment with ethanolic hydrochloric acid or by sequential treatment ofa compound of general formula III with sodium azide followed by eithertriphenylphosphine or hydrogenation over a suitable catalyst.

A second for the preparation of substituted 1,2-nitroamine of generalformula XVII involves the reduction of an imino nitro compound ofgeneral formula XX ##STR17## wherein A¹, A², R, R¹, R², R⁴, R⁵, R⁶, R⁷and B are as defined in general formula I, for example by the action ofsodium cyanoborohydride.

The imino nitro compounds of general formula XX may be prepared bytreating a 1,2-nitroamine of general formula XIII with a substituted ylderivative of general formula XXI ##STR18## wherein R, R⁵, R⁶, R⁷ and Bare as defined in general formula I and R⁴ is a defined in generalformula I but is not a C₁ -C₆ alkylthio. Substituted carbonylderiratives of general formula XXI ray be prepared by treatment of acompound of general formula III with an oxidising agent (e.g. dimethylsulphoxide).

Alternatively substituted 1,2-nitroamines of general formula XVII inwhich R.sup. 4 is hydrogen may be prepared by the reduction of a1,2-nitroamide of general formula XXII ##STR19## wherein A¹, A², R, R¹,R², R⁵, R⁶, R⁷ and B are as defined in general formula I, with asuitable metal hydride reducing agent such as for example lithiumaluminium hydride.

The 1,2-nitroamides of general formula XXII may be prepared by thecoupling of a 1,2-nitroamine of general formula XIII with an acidchloride of general formula XXIII ##STR20## wherein R, R⁵, R⁶, R⁷ and Bare as defined in general formula I, in an aprotiic solvent and in thepresence of a suitable base such as, for example, triethylamine.Alternatively, the reaction may be conducted utilising an acid anhydrideof general formula XXIV ##STR21## wherein R, R⁵, R⁶, R⁷ and B are asdefined in general formula I. Another procedure for preparing1,2-nitroamides of general formula XXII involves reaction of a1,2-nitroamine of general formula XIII with a carboxylic acid of generalformula XXV ##STR22## wherein R, R⁵, R⁶, R⁷ and B are as defined ingeneral formula I, in the presence of a coupling reagent (e.g.1,3-dicyclohexylcarbodiimide). Acid chlorides of general formula XXIII,acid anhydrides of general formula XXIV and carboxylic acids of generalformula XXV may be prepared from carbonyl derivatives of general formulaXXI wherein R⁴ is hydrogen by procedures known to those skilled in theart.

The appropriate solvents employed in the above reactions are solventswherein the reactants are soluble but do not react with the reactants.The preferred solvents vary from reaction to reaction and are readilyascertained by one of ordinary skill in the art.

Compounds of general formulae II, III and IV, XVII are valuableintermediates in the preparation of compounds of general formula I, asare other novel compounds specifically or generically disclosed herein.According to a third aspect of the invention, there is thereforeprovided a compound of general formula II. According to a fourth aspectof the invention, there is provided a compound of general formula III.According to a fifth aspect of the invention, there is provided acompound of general formula IV. According to a sixth aspect of theinvention, there is provided a compound of general formula XVII.

This invention also relates to a method of treatment for patients (oranimals including mammalian animals raised in the dairy, meat, or furtrade or as pets) suffering from disorders or diseases which can beattributed to PAF as previously described, and more specifically, amethod of treatment involving the administration of PAF antagonists ofgeneral formula I as the active ingredient. In addition to the treatmentof warm blooded animals such as mice, rats, horses, cattle, pigs, sheep,dogs, cats, etc., the compounds of the invention are effective in thetreatment of humans.

According to a seventh aspect of the invention there is provided acompound of general formula I for use in human or veterinary medicineparticularly in the management of diseases mediated by PAF; compounds ofgeneral formula I can be used among other things to reduce inflammationand pain, to correct respiratory, cardiovascular, and intravascularalterations or disorders, and to regulate the activation or coagulationof platelets, to correct hypotension during shock, the pathogenesis ofimmune complex deposition and smooth muscle contractions.

According to an eighth aspect of the invention there is provided the useof a compound of general formula I in the preparation of an agent forthe treatment of PAF-mediated diseases, and/or the treatment ofinflammatory disorders such as rheumatoid arthritis, osteoarthritis andeye inflammation, cardiovascular disorder, thrombocytopenia, asthma,endotoxin shock, adult respiratory distress syndrome,glomerulonephritis, immune regulation, gastric ulceration, transplantrejection, psoriasis, allergic dermatitis, urticaria, multiplesclerosis, cerebral, myocardial and renal ischemia and any othercondition in which PAF is implicated.

Compounds of general formula (I) may be administered orally, topically,parenterally, by inhalation spray or rectally in dosage unitformulations containing conventional non-toxic pharmaceuticallyacceptable carriers, adjuvants and vehicles. The term parenteral as usedherein includes subcutaneous imjections, intravenous, intramuscular,intrasternal injection or infusion techniques.

According to a ninth aspect of the invention there is provided apharmaceutical or veterinary formulation comprising a compound ofgeneral formula I and a pharmaceutically and/or veterinarily acceptablecarrier. One or more compounds of general formula I may be present inassociation with one or more non-toxic pharmaceutically and/orveterinarily acceptable carriers and/or diluents and/or adjuvants and ifdesired other active ingredients. The pharmaceutical compositionscontaining compounds of general formula I may be in a form suitable fororal use, for example, as tablets, troches, lozenges, aqueous or oilysuspensions, dispersible powders or granules, emulsion, hard or softcapsules, or syrups or elixirs.

Compositions intended for oral use may be prepared according to anymethod known to the art for the manufacture of pharmaceuticalcompositions and such compositions may contain one or more agentsselected from the group consisting of sweetening agents, flavouringagents, colouring agents and preserving agents in order to providepharmaceutically elegant and palatable preparations. Tablets contain theactive ingredient in admixture with non-toxic pharmaceuticallyacceptable excipients which are suitable for the manufacture of tablets.These excipients may be for example, inert diluents, such as calciumcarbonate, sodium carbonate, lactose, calcium phosphate or sodiumphosphate; granulating and disintegrating agents, for example, cornstarch, or alginic acid; binding agents, for example starch, gelatin oracacia, and lubricating agents, for example magnesium stearate, stearicacid or talc. The tablets may be uncoated or they may be coated by knowntechniques to delay disintegration and absorption in thegastrointestinal tract and thereby provide a sustained action over alonger period. For example, a time delay material such as glycerylmonostearate or glyceryl distearate may be employed.

Formulations for oral use may also be presented as hard gelatin capsuleswherein the active ingredient is mixed with an inert solid diluent, forexample, calcium carbonate, calcium phosphate or kaolin, or as softgelatin capsules wherein the active ingredient is mixed with water or anoil medium, for example peanut oil liquid paraffin, or olive oil.

Aqueous suspensions contain the active materials in admixture withexcipients suitable for the manufacture of aqueous suspensions. Suchexcipients are suspending agents, for example sodiumcarboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose,sodium alginate, polyvinylprrolidone, gum tragacanth and gum acacia;dispersing or wetting agents may be a naturally-occuring phosphatide,for example lecithin, or condensation products of an alkylene oxide withfatty acids for example polyoxyethylene stearate, or condensationproducts of ethylene oxide with long chain aliphatic alcohols, forexample heptadecaethyleneoxycetanol, or condensation products ofethylene oxide with partial esters derived from fatty acids and ahexitol such as polyoxyethylene sorbitol monooleate, or condensationproducts of ethylene oxide with partial esters derived from fatty acidsand hexitol anhydrides, for example polyethylene sorbitan monooleate.The aqueous suspensions may also contain one or more preservatives, forexample ethyl, or n-propyl p-hydroxybenzoate, one or more colouringagents, one or more flavouring agents, and one or more sweeteningagents, such as sucrose or saccharin.

Oily suspensions may be formulated by suspending the active ingredientsin a vegetable oil, for example arachis oil, olive oil, sesame oil orcoconut oil, or in a mineral oil such as liquid paraffin. The oilysuspensions may contain a thickening agent, for example beeswax, hardparaffin or cetyl alcohol. Sweetening agents such as those set forthabove, and flavouring agents may be added to provide a palatable oralpreparations. These compositions may be preserved by the addition of ananti-oxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueoussuspension by the addition of water provide the active ingredient inadmixture with a dispersing or wetting agent, suspending agent and oneor more preservatives. Suitable dispersing or wetting agents andsuspending agents are exemplified by those already mentioned above.Additional excipients, for example sweetening, flavouring and colouringagents may also be present.

Pharmaceutical compositions of the invention may also be in the form ofoil-in-water emulsions. The oily phase may be a vegetable oil, for ampleolive oil or arachis oil, or a mineral oil, for example liquid paraffinor mixtures of these. Suitable emulsifying agents may benaturally-occurring gums, for example gum acacia or gum tragacanth,naturally-occurring phosphatides, for example soy bean, lecithin, andesters or partial esters derived from fatty acids and hexitolanhydrides, for example sorbitan monoleate, and condensation products ofthe said partial esters ethylene oxide, for example palyoxyethylenesorbitan monooleate. The emulsions may also contain sweetening andflavouring agents.

Syrups and elixirs may be formulated with sweetening agents, for exampleglycerol, propylene glycol, sorbitol or sucrose. Such formulations mayalso contain a demulcent, a preservative and flavouring and colouringagents. The pharmaceutical compositions may be in the form of a sterileinjectable aqueous or oleaginous suspension. This suspension may beformulated according to the known art using those suitable dispersing orwetting agents and suspending agents which have been mentioned above.The sterile injectable preparation may also be a sterile injectablesolution or suspension in a non-toxic parentally acceptable diluent orsolvent, for example as a solution in 1,3-butane diol. Among theacceptable vehicles and solvents that may be employed are water,Ringer's solution and isotonic sodium chloride solution. In addition,sterile, fixed oils are conventionally employed as a solvent orsuspending medium. For this purpose any bland fixed oil may be employedincluding synthetic mono-or diglycerides. In addition, fatty acids suchas oleic acid find use in the preparation of injectables.

The compounds of general formula I may also be administered in the formof suppositories for rectal administration of the drug. Thesecompositions can be prepared by mixing the drug with a suitablenon-irritating excipient which is solid at ordinary temperatures butliquid at the rectal temperature and will therefore melt in the rectumto release the drug. Such materials are cocoa butter and polyethyleneglycols.

For topical application to the skin compounds of general formula I maybe made up into a cream, ointment, jelly, solution or suspension etc.Cream or ointment formulations that may be used for the drug areconventional formulations well known in the art, for example, asdescribed in standard text books of pharmaceutics such as the BritishPharmacopoeia.

For topical applications to the eye, compounds of general formula I maybe made up into a solution or suspension in a suitable sterile aqueousor non-aqueous vehicle. Additives, for instance buffers, preservativesincluding bactericidal and fungicidal agents, such as phenyl mercuricacetate or nitrate, benzalkonium chloride or chlorohexidine, andthickening agents such as hypromellose may also be included.

Compounds of general formula I may be administered parenterally in asterile medium. The drug depending on the vehicle and concentrationused, can either be suspended or dissolved in the vehicle.Advantageously, adjuvants such as a local anesthetic, preservative andbuffering agents can be dissolved in the vehicle.

Compounds of general formula I may be used for the treatment of therespiratory tract by nasal or bucal administration of, for example,aerosols or sprays which can disperse the pharmacological activeingredient in the form of a powder or in the form of drops of a solutionor suspension. Pharmaceutical compositions with powder-dispersingproperties usually contain, in addition to the active ingredient, aliquid propellant with a boiling point below room temperature and, ifdesired, adjuncts, such as liquid or solid non-ionic or anionicsurfactants and/or diluents.

Pharmaceutical compositions in which the pharmacological activeingredient is in solution contain, in addition to this, a suitablepropellant, and furthermore, if necessary, an additional solvent and/ora stabiliser. Instead of the propellant, compressed air can also beused, it being possible for this to be produced as required by means ofa suitable compression and expansion device.

Dosage level of the order of from about 0.1 mg to about 140 mg perkilogram of body weight per day are useful in the treatment of the caredconditions (about 0.5 mg to about 7 g per patient per day). For example,inflammation may be effectively treated by administration of from about0.01 to 50 mg of the compound kilogram of body weight per day (about 1.0mg to about 3.5 g per patient per day). The dosage employed for thetopical administration will, of course, depend on the size of the areabeing reared. For the eyes each dose will be typically in the range from10 to 100 mg of the drug.

The amount active ingredient that may be combined with the carriermaterials to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration. For example, aformulation intended for the oral administration of humans may containfrom 0.5 mg to 5 g of active agent compounded with an appropriate andconvenient amount of carrier material which may vary from about 5 toabout 95 percent of the total composition. Dosage unit forms willgenerally contain between from about 1 mg to about 500 mg of an activeingredient.

It will be understood, however, that the specific dose level for anyparticular patient will depend upon a variety of factors including theactivity of the specific compound employed, the age, body weight,general health, sex, diet, time of administration, route ofadministration, rate of excretion, drug combination the severity theparticular disease undergoing therapy.

It has been found that the compounds of general formula I exhibit invitro antagonistic activities with respect to PAF. Compounds of generalformula I inhibit PAF-induced functions in both the cellular and tissuelevels by changing the PAF binding to its specific receptor site. Theability of compounds of general formula I to inhibit the binding of PAFto its specific receptor binding site on human platelet plasma membraneswas measured according to Pharmacological Example 1. The-ability ofcompounds of general formula I to reverse the hypotension caused by aninfusion of PAF in rats was measured according to Pharmacology Example2.

The following examples illustrate the invention, but are not intended tolimit the scope in any way.

The following abbreviations have been used in the Examples:DCM

DCM--Dichloromethane

DIPE--Diisopropylether

DMF--N,N-Dimethylformamide

NBS--N-Bromosuccinimide

THF--Tetrahydrofuran

Unless otherwise stated ¹ H NMR and ¹³ C NMR spectra were recorded on aBruker AC-250 spectrometer at 250 MHz and 62.9 MHz respectively usingCDCl₃ as a solvent and internal reference and are reported as delta ppmfrom TMS.

EXAMPLE 1 N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonylglycinemethyl ester ##STR23## (a) 4-Bromomethylphenylsulphonylchloride

To a solution of p-toluenesulphonyl chloride (50 g, 0.26 mol) in benzene(150 ml) and NBS (46.7 g, 0.26 mol) heated at reflux was added2,2'-azobis(2-methylpropionitrile) (100 mg). The mixture was heated atreflux for 12 h and allowed to cool to room temperature. The whiteprecipitate of succinimide that formed was separated and discarded. Thefiltrate was taken up in DCM (200 ml) and washed with water (3×100 ml)followed by brine (100 ml) and dried over anhydrous sodium sulphate.Filtration, concentration and subsequent crystallisation (from DIPE)gave in two crops 4 -bromomethylphenylsulphonylchloride (46.3 g, 66%) asa white crystalline solid.

m.p. 75°-76° C.

delta_(H) 8.02 (2H, d, J 8.5 Hz), 7.64 (2H, d, J 8.5 Hz), 4.52 (2H, s).

(b) N-4-Bromomethylphenylsulphonyl-glycine methyl ester

To a solution of triethylamine (13.3 ml, 0.096 tool) in dry THF (150 ml)was added powdered glycine methyl ester hydrochloride (6.0 g, 0.048 mol)in one portion. The mixture was stirred at room temperature for 0.5 hand powdered 4-bromomethylphenylsulphonyl chloride (12.9 g, 0.048 mol)added in one portion. The mixture was stirred overnight at roomtemperature. Saturated ammonium chloride (100 ml) was added and themixture extracted with ethyl acetate (3×100 ml), the organics dried overanhydrous sodium sulphate, filtered and evaporated. The resulting oilwas chromatographed (silica: 1:2 hexane: ethyl acetate) to giveN-4-bromomethylphenylsulphonylglycine methyl ester (4.6 g, 28%) as apale yellow oil.

delta_(H) 7.80 (2H, d), 7.44 (2H, d), 5.66-5.60 (1H, m), 4.43 (2H, s),3.79 (2H, d), 3.58 (3H, s).

(c) N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonylglycine methylester

Sodium hydride (60% dispersion in oil) (204 mg, 5.1 mmol) was added to astirred solution of 2-methylbenzimidazole (637 mg, 4.8 mmol) in dry THF(25 ml) under argon at room temperature. After 1 h a solution ofN-4-bromomethylphenylsulphonylglycine methyl ester (820 rag, 2 6 mmol)in dry THF (8 ml) was added. The mixture was stirred for 8 h andsaturated ammonium chloride (60 ml) was added and the product extractedwith ethyl acetate (3×60 ml). The combined organic layers were washedwith water (2×50 ml), dried over anhydrous sodium sulphate, filtered andthe solvent removed. Chromatography (silica: 5% methanol in chloroform)gave N-4-(1H-2-methylbenzimidazolylmethyl)phenyl-sulphonylglycine methylester (193 rag, 20%) as a white crystalline solid.

m.p. 135° C.

Analysis calculated for C₁₈ H₁₉ N₃ SO₄.0.9 H₂ O; Requires C 55.49, H5.38, N 10.78; Found C 55.48, H 5.05, N 10.70.

i.r. (Far) 740, 1325, 1150 cm⁻¹

delta_(H) 7.82 7.68 (3H, m), 7.30-7.14 (5H, m), 5.65-5.50 (1H, m), 5.37(2H, s i, 3.78 (2H, d, J 5.2 Hz), 3.59 (3H, s), 2.56 (3H, s).

EXAMPLE 2N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2,2-dimethylglycinemethyl ester ##STR24## (a) 2,2-Dimethylglycine methyl esterhydrochloride

To a stirred [solution of 2,2-dimethylglycine (10.0 g, 0.097 mol) inmethanol (200 ml) was added trimethylsilyl chloride (37 ml, 0.29 mol).After stirring at room temperature for 14 h. The mixture was evaporatedto dryness to give crude 2,2-dimethylglycine methyl ester hydrochlorideas a white solid which was used directly in the next step.

delta_(H) (CD₃ OD) 4.80 (2H, br s), 3.81 (3H, s), 1.49 (6H, s) .

(b)N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2,2-dimethylglycinemethyl ester

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2,2-dimethylglycine methylester was prepared by the method of Example 1 starting from crude2,2-dimethylglycine methyl ester hydrochloride.

White crystalline solid (20% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 200° C. (dec.)

Analysis calculated for C₂₀ H₂₃ N₃ SO₄ ; Requires C 58.26, H 5.92, N10.19; Found C 58.21, H 5.71, N 9.93.

i.r. (KBr) 1735, 1325, 1145 cm⁻¹

delta_(H) 7.85-7.72 (3H, m), 7.31-7.10 (5H, m), 5.39 (3H, br s), 3.64(3H, s), 2.57 (3H, s), 1.43 (6H, s).

EXAMPLE 3N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-1-aminocyclohexanecarboxylicacid methyl ester ##STR25##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-1-aminocyclohexanecarboxylicacid methyl ester was prepared by the method of Example 2 starting from1-aminocyclohexanecarboxylic acid.

White crystalline solid (26% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 226° C. (sub.)

Analysis calculated for C₂₃ H₂₇ N₃ SO₄.0.9 H₂ O; Requires 60.35, H 6.34,N 9.18; Found 60.29, H 5.98, N 9.10.

i.r. (KBr) 1735, 1325, 1160 cm⁻¹

delta_(H) 7.8 -7.73 (3H, m) , 7.32-7.13 (5H, m) , 5.40 (2H, s) , 4.80(1H, s), 3.49 (3H, s), 2.57 (3H, s), 1.90-1.78 (4H, m), 1.50-1.23 (6H,m).

EXAMPLE 4N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-2-phenylglycinemethyl ester ##STR26##

N-4-(ethylbenzimidazolylmethyl)phenylsulphonyl-L-2-phenylglycine methylester was prepared by the method of Example 2 starting fromL-2-phenylglycine.

White crystalline solid (42% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 50° C.

Analysis calculated for C₂₄ H₂₃ N₃ SO₄.0.8 H₂ O; Requires C 62.13, H5.34, N 9.06; Found C 62.19, H 5.26, N 8.81.

i.r. (KBr) 1740, 1325, 1160 cm⁻¹

delta_(H) 7.79-7.73 (1H, m) , 7.65-7.58 (2H, m) , 7.32-6.98 (10H, m),5.83 (1H, d, J 7.0 Hz), 5.32 (2H, s), 5.08 (1H, d, J 7.0 Hz), 3.55 (3H,s), 2.56 (3H, s).

EXAMPLE 5 N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-valinemethyl ester ##STR27## (a) N-4-Bromomethylphenylsulphonyl-L-valinemethyl ester

To a stirred solution of L-valine methyl ester (2.2 g, 0.019 mol) andtriethylamine (3.2 ml, 0.023 mol) in dry THF (75 ml) was added4-bromomethylphenylsulphonyl chloride (5.5 g, 0.020 mol) in one portion.The mixture was stirred overnight at room temperature. The solvent wasremoved under reduced pressure, the residue dissolved in ethyl acetate(150 ml), washed with water (2×80 ml) and brine (80 ml), dried overanhydrous sodium sulphate, filtered and evaporated. Chromatography(silica: 1:2 hexane:ethyl acetate) gaveN-4-bromomethylphenylsulphonyl-L-valine methyl ester (4.1 g, 76% ) as apale yellow oil.

delta_(H) 7.83 (2H, d, J 8.4 Hz), 7.52 (2H, d, J 8.3 Hz), 5.05 (1H, d, J10.1 Hz), 4.63 (2H, s), 3.76 (1H, m), 3.44 (3H, s), 2.06 (1H, m), 0.97(3H, d, J 6.6 Hz), 0.89 (3H, d, J 6.6 Hz).

(b) N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-valine methylester

Sodium bis(trimethylsilyl)amide (1M solution in THF: 15.5 ml, 0.015 mol)was added to a stirred solution of 2-methylbenzimidazole (1.86 g, 0.014mol) in dry THF (80 ml) under argon at room temperature. After 10 min asolution of N-4-bromomethylphenylsulphonyl-L-valine methyl ester (4.0 g,0.014 mol) in THF (25 ml) was added. The mixture was stirred overnightand the solvent removed under reduced pressure. The residue waspartitioned between DCM (200 ml) and water (60 ml). The organics weredried over anhydrous sodium sulphate filtered and evaporated.Chromatography (silica: 3% methanol in DCM) followed by crystallisationfrom ethyl acetate gave N-4-(1H-2-methylbenzlmidazolylmethyl)phenylsulphonyl-L-valine methyl ester (0.48g, 8) as a white crystalline solid.

m.p. 189° C.

Analysis calculated for C₂₁ H₂₅ N₃ SO₄ ; Requires C 60.70, H 6.06, N10.11; Found C 60.50, H 6.11, N 9.88.

delta_(H) 8.20)(1H, br d), 7.72 (2H, d, J 8.4 Hz), 7.56 (1H, m), 7.33(1H, m), 7.19 (4H, m), 5.52 (2H, s), 3.57 (1H, d, J 6.4 Hz), 3.16 (3H,s), 2.54 (3H, s), 1.91 (1H, m), 0.84 (3H, d, J 6.7 Hz), 0.83 (3H, d, J6i. 8 Hz).

EXAMPLE 6N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-isoleucine methylester ##STR28##

N-4-(1H-2 -Methylbenzimidazolylmethyl)phenylsulphonyl-L-isoleucinemethyl ester was prepared by the method of Example 2 starting fromL-isoleucinie.

White crystalline solid (20% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 197° C.

Analysis calculated for C₂₂ H₂₇ N₃ SO₄ ; Requires C 61.52, H 6.34, N9.78; Found C 61.16, N 6.31, N 9.73.

i.r. (KBr) 2960, 1735, 1325, 1165 cm⁻¹

delta_(H) 7.81-7.72 (3H, m) , 7.33-7.10 (5H, m) , 5.39 (2H, s) , 5.14(1H, d, J 10.0 Hz), 3.77 (1H, dd, J 10.0, 5.4 Hz), 3.33 (3H, s), 2.58(3H, s), 1.82-1.70 (1H, m), 1.24-1.04 (2H, m), 0.95-0.80 (6H, m).

EXAMPLE 7 N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester ##STR29##

N-4-(1H-2-Metlhylbenzimidazolylmethyl)phenylsulphonyl-L-leucine methylester was prepared by the method of Example 5 starting from L-leucinemethyl ester.

White crystalline solid (8% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethylacetate/hexane ): m.p. 201.5°-203° C.

Analysis calculated for C₂₂ H₂₇ N₃ SO₄ ; Requires C 61.52, H 6.34, N9.78; Found C 61.16, H 6.31, N 9.64.

i.r. (CHCl₃) 3360, 1740, 1350, 1160 cm⁻¹

delta_(H) 7.80-7.74 (3H, m), 7.31-7.08 (5H, m), 5.39 (2H, s), 5.08 (1H,d, J 0.0 Hz), 3.92 (1H, dr, J 10.0, 7.3 Hz) 3.34 (3H, s), 2.58 (3H, s),1.82-1.67 (1H, m), 1.50 (2H, t, J 7.3 Hz), 0.88 (3H, d, J 6.6 Hz), 0.85(3H, d, J 6.5 Hz).

EXAMPLE 8 N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-D-leucinemethyl ester ##STR30##N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-D-leucine methylester was prepared by the method of Example 5 starting from D-leucinemethyl ester.

White crystalline solid (6% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethyl acetate):m.p. 204.5°-206.5° C.

Analysis calculated for C₂₂ H₂₇ N₃ SO₄ ; Requires C 61.51, H 6.34, N9.78; Found C 61.55, H 6.38, N 9.73.

delta_(H) 7.80-7.74 (3H, m) , 7.31-7.08 (5H, m) , 5.39 (2H, s) , 5.08(1H, d, J 10.0 Hz) , 3.92 (1H, dr, J 10.0, 7.3 Hz), 3.34 (3H, s), 2.58(3H, s), 1.82-1.67 (1H, m), 1.50 (2H, t, J 7.3 Mz), 0.88 (3H, d, J 6.6Hz) 0.85 (3H, d, J 6.5 Hz).

EXAMPLE 9N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-norleucine methylester ##STR31##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-norleucine methylester was prepared by the method of Example 2 starting fromL-norleucine.

White crystalline solid (10% yield for last step after chromatography(silica: 5% methanol in DCM) and crystallisation from ethyl acetate):m.p. 172° C.

Analysis calculated for C₂₂ H₂₇ N₃ SO₄ ; Requires C 61.52, H 6.34, N9.78; Found C 61.49, H 6.23, N 10.01.

i.r. (KBr) 1750, 1330, 1160 cm⁻¹

delta_(H) 7.80-7.65 (3H, m), 7.30-7.06 (5H, m), 5.70 (1H, br d, J 8.4Hz), 5.34 (2H, s), 3.95-3.80 (1H, m), 3.37 (3H, s), 2.55 (3H, s),1.75-1.50 (2H, m), 1.32-1.16 (4H, m), 0.81 (3H, t, J 6.8 Hz).

EXAMPLE 10N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester ##STR32##

N-4-(1H-2 -Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester was prepared by the method of Example 5 starting fromL-phenylalanine methyl ester.

White crystalline solid (27% yield for last step after chromatography(silica: 2% methanol in DCM)): m.p. 126° C.

Analysis calculated for C₂₅ H₂₅ N₃ O₄ S; Requires C 64.77, H 5.44, N9.07; Found C 64.60, H 5.51, N 9.04.

i.r. (KBr) L735, 1340, 1150 cm⁻¹

delta_(H) 7.8017.63 (3H, m), 7.34-6.99 (10H, m), 5.37 (2H, s), 5.04 (1H,d, J 9.2 Hz), 4,24-4.13 (1H, m), 3.45 (3H, s), 3.04 (1H, dd, J 13.8, 5.8Hz), 2.98 (1H, dd, J13.8, 6.3 Hz), 2.57 (3H, s).

EXAMPLE 11N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-methyl-L-tyrosinemethyl ester ##STR33## (a) N-Benzyloxycarbonyl-O-methyl-L-tyrosine

N-Benzyloxycarbonyl-L-tyrosine (31.5 g, 0.1 mol) was dissolved inaqueous sodium hydroxide (10 g in 100 ml H₂₀) and dimethylsulphate (10.5ml, 0 11 mol) added dropwise to the stirred solution. The reaction wasstirred overnight, additional dimethylsulphate (2 ml) added in oneportion and the reaction stirred for a further 48 hours. 2M Hydrochloricacid was added until a white precipitate formed. This was filtered off,taken up in ethyl acetate, washed with brine and dried over anhydroussodium sulphate, filtered and evaporated. The residue was crystallisedfrom ethyl acetate to give N-benzyloxycarbonyl-O-methyl-L-tyrosine (5.8g, 18%) as a white crystalline solid.

m.p. 106°-108 ° C.

delta_(H) 7.26-6.96 (7H, m), 6.98 (2H, d, J 8.0 Hz), 5.61 (1H, s), 5.00(1H, br d) , 4.77 (1H, br d), 4.40 (1H, br m), 3.63 (3H, s), 3.09 (1H,br m) , 2.84 (1H, br m) .

(b) O-Methyl-L-tyrosine

N-Benzyloxycarbonyl-O-methyl-L-tyrosine (5.7g, 17.3 mmol) was dissolvedin ethanol (50 ml) and the solution added to a suspension of 10%palladium on charcoal (100 mg) in cyclohexene (10 ml). The reaction wasthen heated at reflux for 1 h, allowed to cool to ambient temperature,filtered, and the filtrate concentrated to give O-methyl-L-tyrosine (1.4g, 43%) as a white solid which was used directly in the next step.

(c) O-Methyl -L-tyrosine methyl ester

A solution of O-methyl-L-tyrosine (1.44 g, 7.4 mmol) in methanol (30 ml)was stirred at 0° C. and thionyl chloride (1 ml, 13.4 mmol) addeddropwise. After stirring for 15 min. at ambient temperature the reactionwas heated at reflux for 2 h. After cooling the solvent was evaporatedto give crude O-methyl-L-tyrosine methyl ester hydrochloride salt as ayellow solid. This was partitioned between saturated aqueous sodiumhydrogen carbonate (80 ml) and ethyl acetate (150 ml), and the aqueouslayer back extracted with ethyl acetate (2×80 ml). The combined organicswere dried over anhydrous s odium sulphate, filtered and concentrated togive O-methyl-L-tyrosine methyl ester as a yellow oil.

delta_(H) 7.07 (2H, d, J 8.5 HZ), 6.80 (2H, d, J 8.5 HZ), 3.75 (3H, s),3.68 (Ill, s) , 3.67 (1H, m) , 2.99 (1H, dd, J 13.6, 5.2 Hz) , 2.79 (1H,dd, J 13.6, 7.7 Hz), 1.85 (2H, br s).

(d) N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-methyl-L-tyrosine methylester

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-methyl-L-tyrosine methylester was prepared from O-methyl-L-tyrosine methyl ester by a similarprocedure to that used in Example 5.

White crystalline solid (4 % yield for last step after chromatography(silica: 3% methanol in DCM)): m.p. 168°-170° C.

delta_(H) 7.75-7.60 (3H, m), 7.27-7.04 (7H, m), 6.70 (2H, d, J 6.8 Hz),5.70 (1H, br d), 5.32 (2H, s), 4.15 (1H, m), 3.71 (3H, s), 3.41 (3H, s),2.93 (2H, dd, J 6.4, 3.5 Hz), 2.54 (3H, s).

EXAMPLE 12 N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-benzyl-L-serine methylester ##STR34##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-O-benzyl-L-serinemethyl ester was prepared by the method of Example 5, starting fromO-benzyl-L-serine methyl ester.

White crystalline solid (7% yield for last step after chromatography(silica: 1% methanol in DCM)):m.p. 125° C.

Analysis calculated for C₂₆ H₂₇ N₃ SO₄.0.6 H₂ O Requires C 61.91, H5.64, N 8.33; Found C 61.87, H 5.52, N 8.27.

i.r. (KBr) 1745, 1325, 1160 cm⁻¹

delta_(H) 7.80-7.70 (3H, m) , 7.31-7.04 (10H, m) , 5.70-5.60 (1H, m) ,5.36 (2H, s) , 4.42 (2H, dd, J 12.1 Hz) , 4.18-4.06 (1H, m) , 3.76 (1H,dd, J 9.5, 3.4 Hz), 3.60 (1H, dd, J 9.5, 3.5 Hz) , 3.49 (3H, s), 2.55(3H, s).

EXAMPLE 13N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-methionine methylester ##STR35##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-methionine methylester was prepared by the method of Example 1 starting from L-methioninemethyl ester hydrochloride.

White crystalline solid (4% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 144° C. (dec.)

Analysis calculated for C₂₁ H₂₅ N₃ S₂ O₄.1.0 H₂ O; Requires C 54.17, H5.85, N 9.03; Found C 54.16, H 5.53, N 8.86.

i.r. (KBr) 1740, 1325, 1115 cm⁻¹

delta_(H) 7.86-:7.71 (3H, m) , 7.30-7.12 (5H, m) , 5.57 (1H, d, J 9.1Hz), 5.38 (2H, s), 4.07 (1H, m), 3.45 (3H, s), 2.58 (3H, s), 2.61-2.41(2H, m), 2.03 (3H, s), 2.03-1.80 (2H, m).

EXAMPLE 14N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine ethylester ##STR36##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine ethylester was prepared by the procedures of Example 11 step (c) and Step (d)starting from L-leucine and ethanol.

White crystalline solid (2% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethylacetate/hexane): m.p. 205.5°-207° C.

Analysis calculated for C₂₃ H₂₉ N₃ SO₄ ; Requires C 62.28, H 6.59, N9.47; Found C 62.09, H 6.59, N 9.34.

delta_(H) 7.79 (2H, d, J 8.5 Hz), 7.76 (1H, d, J 1.1 Hz), 7.20 (5H, m),5.38 (2H, s), 5.11 (1H, d, J 10.0 Hz), 3.89 (1H, dr, J 10.0, 7.2 Hz),3.75 (2H, dq, J 7.3, 3.5 Hz), 2.58 (3H, s), 1.75 (1H, m), 1.46 (2H, t, J7.2 Hz), 0.97 (3H, t, J 7.2 Hz), 0.88 (3H, d, J 6.8 Hz), 0.86 (3H, d, J6.8 Hz).

EXAMPLE 15N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalanineethyl ester ##STR37##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalanineethyl ester was prepared by the procedures of Example 11 Step (c) andStep (d) starting from L-phenylalanine and ethanol.

White crystalline solid (5% yield after chromatography (silica: 3%methanol in DCM) and crystallisation from ethyl acetate/hexane): m.p.219°-220.5° C.

Analysis calculated for C₂₆ H₂₇ N₃ SO₄.0.5H₂ O; Requires C 64.18, H5.80, N 8.64; Found C 64.2 6, H 5.67, N 8.57.

delta_(H) 7.75 (1H, dd, J 7.0, 1.3 Hz), 7.67 (2H, d, J 8.4 Hz), 7.16(10H, m), 5.35 (2H, s), 5.25 (1H, d, J 9.3 Hz), 4.16 (1H, dr, J 9.2, 6.2Hz), 3.81 (2H, dq, J 7.2, 4.3 Hz), 2.98 (2H, d, J 6.3 Hz), 2.56 (3H, s),1.00 (3H, t, J 7.1 Hz).

EXAMPLE 16N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-methionine ethylester ##STR38##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-methionine ethylester was prepared by the method of Example 1 starting from L-methioniteethyl ester hydrochloride.

White crystalline solid (13% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 78° C.

i.r. (KBr) 1740, 1320, 1155 cm⁻¹

delta_(H) 7.80-7.70 (3H, m), 7.27-7.10 (5H, m) , 5.80 (1H, d, J 9.0 Hz),5.35 (2H, s), 4.02 (1H, m), 3.93-3.78 (2H, m), 2.55 (3H, s), 2.60-2.42(2H, m), 2.01 (3H, s), 2.03-1.78 (2H, m), 1.02 (3H, t, J 7.2 Hz).

EXAMPLE 17N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-aspartic aciddiethyl ester ##STR39##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-aspartic aciddiethyl ester was prepared by the method of Example 1 starting fromL-aspartic acid diethyl ester hydrochloride.

White crystalline solid (13% yield for last step after chromatography(silica: 5% methanol in chloroform)): m.p. 140° C.

Analysis calculated for C₂₄ H₂₉ N₃ SO₆ ; Requires C 59.12, H 6.00, N8.62; Found C 58.94, H 5.98, N 8.50.

delta_(H) 7.78-7.69 (3H, m), 7.30-7.11 (5H, m), 5.72 (1H, d, J 9.3 Hz),5.35 (2H, s), 4.10 (2H, q, J 7.2 Hz), 4.00-3.73 (3H, m), 2.55 (3H, s),2.48-2.38 (2H, m), 2.18-2.02 (1H, m), 1.93-1.78 (1H, m), 1.23 (3H, t, J7.2 Hz), 0.99 (3H, t, J 7.2 Hz).

EXAMPLE 18N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine isopropylester ##STR40##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine isopropylester was prepared by the procedures of Example 11 Step (c) and Step (d)starting from L-leucine and isopropanol.

White crystalline solid (11% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethylacetate/hexane): m.p. 191°-192° C.

Analysis calculate for C₂₄ H₃₁ N₃ SO₄ ; Requires C 62.75, H 6.85, N9.23; Found C 62.73, H 6.81, N 9.23.

delta_(H) 7.82-7.70 (3H, m), 7.30-7.10 (5H, m), 5.37 (2H, s), 5.13 (1H,d, J 10 .0 Hz), 4.62-4.51 (1H, m), 3.86 (1H, dr, J 10.0, 7.4 Hz), 2.57(3H, s), 1.84-1.72 (1H, m), 1.44 (2H, t, J 7.4 Hz), 1.03 (3H, d, J 6.3Hz) , 0.93-0.81 (9H, m) .

EXAMPLE 19N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine n-butylester ##STR41##

N-4-(1H-2-Melthylbenzimidazolylmethyl)phenylsulphonyl-L-leucine n-butylester was prepared by the method of Example 11 Step (c) and Step (d)starting from L-leucine and n-butanol.

White solid (43% yield for last step after chromatography (silica:methanol in DCM) ): m.p. 111°-113° C.

i.r. (CHCl₃) 3020, 1735, 1345, 1185 cm⁻¹

delta_(H) 7.78-7.70 (3H, m), 7.25-7.11 (5H, m), 5.36 (2H, s), 5.01 (1H,d, J 9.9 Hz), 3.88 (1H, m), 3.77-3.58 (2H, m), 2.54 (3H, s), 1.73 (1H,m), 1.46-1.10 (6H, m), 0.88-0.79 (9H, m).

delta_(C) 172.13, 151.47, 145.39, 140.67, 139.77, 128.03, 126.77,122.71, 122.52, 119.33, 109.02, 65.32, 54.46, 46.66, 42.36, 30.23,24.29, 22.67, 21.40, 16.93, 13.63.

EXAMPLE 20N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-alanine-tert-butylester ##STR42##N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-alaninetert-butyl ester was prepared by the method of Example 1 starting fromL-alanine tert-butyl ester hydrochloride.

White crystalline solid (6% yield for last step after chromatography(silica: 5% methanol in DCM)): m.p. 81° C.

i.r. (KBr) i735, 1325, 1160 cm⁻¹

delta_(H) 7.83-7.72 (3H, m), 7.33-7.11 (5H, m), 5.40 (2H, s), 5.37 (1H,d, 14.b 3 HZ) , 3.86 (1H, dr, J 14.3, 7.2 Hz) , 2.56 (3H, s), 1.34 (3H,d, J 7.2 Hz) 1.25 (s, 9H).

delta_(C) 169.73, 151.37, 141.51, 140.50, 140.17, 134.79, 128.02,126.77, 122.98, 122.82, 119.10, 109.16, 51.99, 46.66, 27.66, 18.63,12.24.

EXAMPLE 21N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninetert-butyl ester ##STR43##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninetert-butyl ester was prepared by the method of Example 5 starting fromL-phenylalanine tert-butyl ester.

White crystalline solid (7% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethylacetate/hexane): m.p. 165.5°-166.5° C.

Analysis calculated for C₂₈ H₃₁ N₃ SO₄ ; Requires C 66.51, H 6.18, N8.31; Found C 66.16, H 6.22, N 8.29.

i.r. (CDCl₃) 3040, 1740, 1345, 1160 cm⁻¹

delta_(H) 7.72 (3H, m), 7.19 (10H, m), 5.35 (2H, s), 5.18 (1H, d, J 9.3Hz), 4.07 (1H, dr, J 9.3, 6.2 Hz), 2.99 (2H, d, J 6.1 Hz), 2.55 (3H, s),1.17 (9H, s).

EXAMPLE 22N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine benzylester ##STR44##

N-4-(1H-2 -Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine benzylester was prepared by the method of Example 5 starting from L-leucinebenzyl ester.

White crystalline solid (4% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethylacetate/hexane): m.p. 130.5°-133° C.

Analysis calculated for C₂₈ H₃₁ N₃ SO₄.0.2 H₂ O; Requires C 66.04, N6.22, N 8.25; Found C 66.02, H 6.21, N 8.19.

delta_(H) 7.75 (3H, m), 7.22 (10H, m), 5.37 (2H, s), 5.03 (1H, d, J 10.1Hz), 4.81 (1H, d, J 12.3 Hz), 4.72 (1H, d, J 12.2 Hz), 3.98 (1H, dr, J10.1, 7.4 Hz), 2.56 (3H, s), 1.74 (1H, m), 1.48 (2H, t, J 7.3 Mr), 0.87(3H, d, J 6.6 Hz), 0.84 (3H, d, J 6.7 Hz).

EXAMPLE 23N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninebenzyl ester ##STR45##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninebenzyl ester was prepared by the procedures of Example 11 Step (c) andStep (d) starting from L-phenylalanine and benzyl alcohol.

White crystalline solid (3% yield for last step after chromatography(silica: 3% methanol in DCM) and crystallisation from ethylacetate/hexane): m.p. 114° C.

Analysis calculated for C₃₁ H₂₉ N₃ SO₄ ; Requires C 68.29, H 5.54, N7.96; Found C 68.77, H 5.43, N 7.74.

delta_(H) 7.75 (1H, dd, J 6.8, 1.4 Hz), 7.66 (2H, m), 7.21 (15H, m),5.35 (2H, s, 5.13 (1H, d, J 9.27 Hz), 4.83 (2H, dd, J 12.1, 7.4 Hz),4.24 (H, dr, J 9.3, 6.0 Hz), 3.02 (2H, d, J 6.0 Hz), 2.56 (3H, s).

EXAMPLE 24N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-isoleucinemethylamide ##STR46##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-isoleucinemethylamide was prepared by the method of Example 5 starting fromL-isoleucine methylamide.

Colourless oil (0.3% yield for last step after chromatography (silica:1% methanol in DCM)).

delta_(H) 7.84-7.70 (3H, m), 7.38-7.12 (6H, m), 5.37 (2H, s), 5.36-5.24(1H, m), 3.84-3.74 (1H, m), 3.33 (3H, s), 2.57 (3H, s), 1.84-1.70 (1H,m), 1.46-1.04 (2H, m), 0.98-0.80 (6H, m).

EXAMPLE 25N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethylamide ##STR47## (a) N-Benzyloxycarbonyl-L-phenylalaninemethylamide

To a stirred solution of N-benzyloxycarbonyl-L-phenylalaninep-nitrophenylester (5.0 g, 11.9 mmol) in DCM at 0° C. was slowly added asolution of 8M methylamine (1.5 ml, 11.9 mmol) in ethanol. The reactionimmediately turned bright yellow and was stirred for 0.5 h. The reactionwas diluted with DCM (50 ml), washed with 10% sodium carbonate (1×50ml), brine (2×50 ml) and dried over anhydrous magnesium sulphate.Filtration and evaporation gave a white residue which was crystallisedfrom ethyl acetate/hexane to give N-benzyloxycarbonyl-L-phenylalaninemethylamide (3.0 g, 81%) as a white crystalline solid.

m.p. 153°-154° C.

delta_(H) 7.38-7.17 (10H, m), 5.62 (1H, br s), 5.32 (1H, br s), 5.09(2H, s), 4.35 (1H, dd, J 14.4, 7.5 Hz), 3.12-2.99 (2H, m), 2.72 (3H, d,J 4.9 Hz).

(b) L-Phenylalanine methylamide

L-Phenylalanine methylamide was prepared following the method of Example1Step (b) starting from N-benzyloxycarbonyl-L-phenylalanine methylamide.

Brown-red solid (1.6 g, 97%).

delta_(H) 7.36-7.21 (6H, m), 3.61 (1H, dd, J 9.5, 4.0 Hz), 3.30 (1H, dd,J 13.7, 4.0 Hz), 2.82 (3H, d, J 5.0 Hz), 2.68 (1H, dd, J 13.7, 9.5 Hz),1.48 (2H, br s).

(c) N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethylamide

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemethylamide was prepared from L-phenylalanine methylamide by a similarprocedure to that used in Example 5.

White crystalline solid (3% yield for last step after chromatography(silica: 5% methanol in DCM) and crystallisation from ethylacetate/hexane): m.p. 204° C.

i.r. (CHCl₃) 3450, 1760, 1345, 1165 cm⁻¹

delta_(H) 7.77 (1H, br d), 7.56 (2H, br d), 7.32-7.06 (8H, m), 6.89 (2H,m), 6.a5 (1H, br d), 5.39 (2H, s), 5.01 (1H, br d), 3.78 (1H, dd, J13.5, 6.7 Hz), 2.91 (2H, m), 2.68 (3H, d, J 4.9 Hz), 2.60 (3H, s).

EXAMPLE 26N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalanine2-pyridylamide ##STR48##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalanine2-pyridylamide was prepared following the method of Example 25 startingfrom N-benzyloxycarbonyl-L-phenylalanine p-nitrophenyl ester and2-aminopyridine.

White crystalline solid (7% yield for last step after chromatography(silica: 5% methanol in DCM)): m.p. 205°-207° C.

i.r. (KBr) 1675, 1330, 1160 cm⁻¹

delta_(H) 8.58 (1H, br s), 8.26 (1H, br d), 8.06 (1H, br d), 6.92-7.78(15H, m), 5.55 (1H, br d), 5.30 (2H, s), 4,04 (1H, br d), 3.05 (2H, m)2.51 (3H, s) .

EXAMPLE 27N-4-(1H-2-Methylbenzimidazlylmethyl)phenylsulphonyl-L-phenylalaninemorpholinoamide ##STR49## (a) N-tert-Butoxycarbonyl-L-phenylalaninemorpholinoamide

N-tert-Butoxycarbonyl-L-phenylalanine morpholinoamide was preparedfollowing the procedure of Example 25 Step (a) starting fromN-tert-butoxycarbonyl-L-phenylalanine p-nitrophenyl ester andmorpholine.

delta_(H) 7.33-7.18 (5H, m), 5.48 (1H, d J 8.6 Hz), 4.83-4.74 (1H, m),3.61-3.20 (6H, m), 3.05-2.80 (4H, m), 1.41 (9H, s).

(b) L-Phenylalanine morpholinoamide

Trifluoroacetic acid (2.5 ml) was added to a stirred solution ofN-tert-butoxycarbonyl-L-phenylalanine p-nitrophenyl ester (1.0 g, 3.0mmol) in DCM (20 ml) at 0° C. After 10 min the mixture was allowed towarm up to room temperature, stirred for 2.5 h and concentrated. Theresidue was dissolved in methanol (100 ml) and treated with basicAMBERLITE resin (IR-45), stirred for 10 min, filtered and concentrated.(The Word AMBERLITE is a trade mark.) Crystallisation from ethyl acetategave L-phenylalanine morpholinoamide as a white crystalline solid.

delta_(H) 7.40-7.12 (5H, m), 4.60 (2H, s), 4.30-2.87 (11H, m).

(c)N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaniniemorpholinoamide

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-phenylalaninemorpholinoamide was prepared by the method of Example 5 starting fromL-phenylalanine morpholinoamide.

White crystalline solid (9% yield for last step after chromatography(silica: 1% methanol in DCM)): m.p. 90° C.

i.r. (Far) 1635, 1325, 1115 cm⁻¹

delta_(H) 7.80-7.64 (3H, m), 7.30-7.03 (10H, m), 6.28 (1H, d, J 9.6 Hz),5.34 (2H, s), 4.40-4.30 (1H; m), 3.40-2.51 (10H, m), 2.57 (3H, s).

delta_(C) 168.78, 151.44, 142.17, 140.81, 140.08, 135.23, 134.79,129.42, 128.65, 127.74, 127 37, 126 62, 122.70, 122.52, 119.25, 109.02,53.09, 46.51, 45.57, 41.97, 40.73.

EXAMPLE 28N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-leucinepyrrolidinoamide ##STR50##

N-4-(1H-2-Methylbenzimidazolylmethyl) phenylsulphonyl-L-leucinepyrrolidinoamide was prepared by the method of Example 5 Step (a) andExample 1 Step (c) starting from L-leucine pyrrolidinoamide.

White crystlalline solid (6% yield for last step after chromatography(silica: 5% methanol in DCM)):m.p. 126°

i.r. (CDCl₃) 1635, 1340, 1160 cm⁻¹

delta_(H) 7.80-7.70 (3H, m) , 7.30-7.10 (5H, m) , 5.56 (1H, d, J 9.9Hz), 5.39-5.30 (2H, m), 4.00-3.83 (1H, m), 3.20-3.02 (3H, m), 2.78-2.60(1 m), 2.58 (3H, s), 2.00-1.10 (7H, m), 0.95-0.83 (6H, m).

delta_(C) 169.219, 151.43, 142.71, 140.86, 139.82, 135.01, 128.00,126.55, 122.58, 122.41, 119.48, 108.88, 53.12, 46.58, 45.88, 45.73,42.03, 25.79, 24.07, 23.79, 23.28, 21.09.

EXAMPLE 29N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-prolinyl methylester ##STR51##

N-4-(1H-2-Methylbenzimidazolylmethyl)Phenylsulphonyl-L-prolinyl methylester was prepared following the procedure of Example 1 starting fromL-prolinyl methyl ester hydrochloride.

Colourless viscous oil (30% yield for last step after chromatography(silica: 5% methanol in chloroform)).

delta_(H) 7.83-7.70 (3H, m), 7.31-7.12 (5H, m) , 5.37 (2H, s) , 4.31(1H, dd, J 7.7, 4.0 Hz), 3.65 (3H, s), 3;48-3.24 (2H, m), 2.55 (3H, s) ,2.12-1.72 (4M, m).

delta_(C) 172.32, 151.56, 142.55, 140.92, 138.30, 129.40, 128.12,126.74, 122.51, 122.29, 119.26, 109.02, 60.25, 52.27, 48.20, 46.54,30.80, 24.56.

EXAMPLE 30N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-prolinylbenzylester ##STR52##

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-L-prolinyl benzylester was prepared following the procedure of Example 1 starting fromL-prolinyl benzyl ester hydrochloride.

Colourless viscous oil (13% yield for last step after chromatography(silica: 5% methanol in chloroform)). delta_(H) 7.82-7.73 (3H, m),7.36-7.08 (10H, m), 5.35 (2H, s), 5.10 (2H, s) , 4.40 (1H, dd, J 8.0,3.8 Hz), 3.47-3.26 (2H, m) , 2.55 (3H, s), 2.17-1.76 (4H, m).

delta_(C) 171.67, 151.54, 142.64, 140.89, 138.41, 135.29, 135.13,128.50, 128.31, 128.17, 128.03, 126.68, 122.49, 122.28, 119.32, 109.02,66.98, 60.35, 48.17, 46.54, 30.83, 24.60.

EXAMPLE 31

(A) N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine methylester and (B)N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine methylester ##STR53##

N-4-(3 H- Imidazo[4,5 -c]pyridylmethyl)phenylsulphonyl-L-leucine methylester and N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester were prepared by the method of Example 7 employing in thefinal step imidazo[4,5-c]pyridine in lieu of 2-methylbenzimidazole andusing 1:1 DMF:THF as solvent. Chromatography (silica: 8% methanol inDCM) gave N-4-(3H-imidazo [4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester (regioisomer A) which eluted first followed byN-4-(1H-imidazo [4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine methylester (regioisomer B).

Regioisomer (A): Orange amorphous solid (3% yield for last step afterchromatography).

i.r. (CHCl₃) 3020, 1740, 1420, 1190 cm⁻¹

delta_(H) 8.71 (1H, br s), 8.48 (1H, br d), 8.13 (1H, s), 7.74-7.82 (3H,m), 7.31 (2H, d, J 8.4 Hz), 6.00 (1H, br s), 5.52 (2H, s), 3.93 (1H, brm), 3.34 (3H, s), 1.74 (1H, m), 1.49 (2H, dd, J 7.3, 6.2 Hz), 0.87 (3H,d, J 6.9 Hz), 0.84 (3H, d, J 7.2 Hz).

Regioisomer (B): White amorphous solid (10% yield).

i.r. (CHCl₃) 3015, 1740, 1420, 1185 cm⁻¹

delta_(H) 9.14 (1H, br s) , 8.40 (1H, br d), 8.06 (1H, s) , 7.78 (2H, d,J 8.4 Hz), 7.25 (2H, d, J 8.4 Hz), 7.17 (1H, d, J 5.5 Hz), 6.08 (1H, brs), 5.45 (2H, s), 3.93 (1H, br d), 3.33 (3H, s), 1.73 (1H, m), 1.48 (2H,dd, J 7.3, 7.0 Hz), 0.86 (3H, d, J 6.7 Hz), 0.82 (3H, d, J 6.5 Hz).

EXAMPLE 32

(A) N-4-(3H-2 -Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine methyl ester and(B)N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester ##STR54##

N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester andN-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemethyl ester were prepared by the method of Example 7 employing in thefinal step 2-methylimidazo [4,5-c]pyridine in lieu of2-methylbenzimidazole and using 1:1 DMF:THF as solvent. Chromatography(silica: 2% methanol in DCM) gaveN-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl) phenylsulphonyl-L-leucinemethyl ester (regioisomer A) which eluted first followed byN-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl) phenylsulphonyl-L-leucinemethyl ester (regioisomer B) which was crystallised fromchloroform/hexane.

Regioisomer (A) : White crystalline solid; m.p. 198° C. (dec.).

Analysis calculated for C₂₁ H₂₆ N₄ O₄ S Requires C 58.58, H 6.09, N13.02; Found C 58.56, H 6.09, N 12.95.

i.r. (CDCl₃) 2960, 2240, 1735, 1345, 1160 cm⁻¹

delta_(H) 8.85 (1H, br s), 8.46 (1H, d, J 7.9 Hz), 7.83 (2H, d, J 8.3Hz), 7.76 (1H, d, J 5.6 Hz), 7.21 (2H, d, J 8.3 Hz), 5.56 (2H, s), 5.31(1H, d, J 10.1 Hz), 3.93 (1H, m), 3.42 (3H, s), 2.67 (3H, s), 1.74 (1H,m), 1.50 (2H, dd, J 7.3, 7.0 Hz), 0.89 (3H, d, J 6.7 Hz), 0.86 (3H, d, J6.5 Hz).

Regioisomer (B): White crystalline solid (93 rag, 3% yield): m.p. 191°C. (dec.).

Analysis calculated for C₂₁ H₂₆ N₄ O₄ S.0.75CHCl₃ ; Requires C 50.23, H5.18, N 10.77; Found C 50.38, H 5.29, N 10.61.

i.r. (CDCl₃) 1725, 1375, 1160 cm⁻¹

delta_(H) 9.06 (1H, s), 8.39 (1H, d, J 5.6 Hz), 7.80 (2H, d, J 8.4 Hz),7.20-7.10 (3H, m), 5.40 (2H, s), 5.04 (1H, d, J 9.6 Hz), 4.00-3.90 (1H,m), 3.38 (3H, s), 2.61 (3H, s), 1.80-1.67 (1H, m), 1.48 (2H, t, J 7.2Hz), 0.88 (3H, d, J 6.6 Hz), 0.86 (3H, d, 6.4 Hz).

EXAMPLE 33

(A) N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester and (B)N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester ##STR55##

(A) N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester and (B)N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester were prepared by the method of Example 10. In the finalstep imidazo[4,5-c]pyridine was employed in lieu of2-methylbenzimidazole.

Regioisomer_(i) (A): Pale yellow crystalline-solid (0.5% yield for laststep a chromatography (silica: 5% methanol in DCM)): m.p. 136° C. (dec)

i.r. (CDCl₃) 1740, 1340, 1155 cm⁻¹

delta_(H) 8.71 (1H, s), 8.47 (1H, br d, J 5.6 Hz), 8.11 (1H, s), 7.76(1H, d, J 5.5 Hz), 7.75-7.64 (2H, m), 7.30-7.00 (7H, m), 5.82-5.62 (1H,m), 5.49 (2H, s), 4.24-4.14 (1H, m), 3.46 (3H, s), 3.13-2.91 (2H, m).

Regioisomer (B): White crystalline solid (0.6% yield).

delta_(H) 0.17 (1H, s), 8.43 (1H, d, J 5.5 Hz), 8.05 (1H, s), 7.75-7.64(2H, m, 7.25-7.00 (5H, m), 5.44 (2H, s), 4.26-4.18 (1H, m), 3.46 (3H,s), 3.12-2.94 (2H, m).

EXAMPLE 34

(A)N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-O-benzyl-L-serinemethyl ester and (B)N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-O-benzyl-L-serinemethyl ester ##STR56##

(A) N-4-(3H-Imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester and (B)N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-phenylalaninemethyl ester were prepared by the method of Example 12. In the finalstep imidazo[4,5-c]pyridine was employed in lieu of2-methylbenzimidazole.

Regioisomer (A): White crystalline solid (5% yield for last step afterchromatography (silica: 2% methanol in DCM)): m.p. 160° C.

i.r.(CDCl₃) 1750, 1340, 1160 cm⁻¹

delta_(H) 8.69 (1H, s), 8.48 (1H, d, J 5.6 Hz), 8.08 (1H, s), 7.84-7.75(3H, m), 7.38-7.14 (7H, m), 6.10 (1H, br s), 5.48 (2H, s), 4.46 (1H, d,! J 12.0 Hz), 4.39 (1H, d, J 12.0 Hz), 4.20-4.10 (1H, m), 4.19-4.10 (1H,br s), 3.79 (1H, dd, J 9.3, 3.4 Hz), 3.63 (1H, dd, J 9.3, 3.5 Hz), 3.51(3H, s).

Regioisomer (B) : White crystalline solid (3% yield): m.p. 156° C.

i.r. (KBr) 1740, 1335, 1160 cm⁻¹

delta_(H) 9.16 (1H, s), 8.40 (1H, d, J 5.6 Hz), 8.03 (1H, s), 7.79 (2H,d, J 8.4 Hz), 7.33-7.12 (8H, m), 6.22 (1H, br s), 5.41 (2H, s), 4.41(2H, dd, J 12, 12 Hz), 3.79 (1H, dd, J 9.4, 3.4 Hz), 3.62 (1H, dd, J9.4, 3.5 Hz), 3.48 (3H, s).

EXAMPLE 35

(A) N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethylester and (B)N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR57##

(a) N-4-Bromomethylphenylsulphonyl-L-leucine ethyl ester

L-leucine ethyl ester hydrochloride (1) (75.0 g. 0.403 mol) wassuspended in THF (300 ml) at 0° C., and triethylamine (67 ml, 0.484 mol)added =slowly. After stirring for 15 min. a solution of4-bromomethylsulphonyl chloride (108.4 g, 0.403 mol) in dry THF (100 ml)was added via cannular. The reaction mixture was allowed to stirovernight at ambient temperature. The solvent was removed under lowpressure and the organics were extracted into ethyl acetate (200 ml) andwashed with water (100 ml) and brine (100 ml). The organic portion wasdried over anhydrous magnesium sulphate, filtered and the solventevaporated under low pressure. The product was recrystallised from DIPE(500 ml) to give N-4-bromomethylpihenylsulphonyl-L-leucine ethyl ester(134 g, 85%) as a white crystalline solid.

[α]_(D) ²⁰ +21.8 (c 2.2, DCM)

i.r. (DCM) 3325, 1735, 1340, 1160 cm⁻¹

delta_(H) 7.84 (2H, d, J 8.3 Hz), 7.52 (2H, d, J 8.3 Hz), 5.06 (1H, d, J10.1 Hz, 4.61 (2H, s), 3.97-3.82 (3H, m), 1.85-1.79 (1H, m), 1.49 (2H,t, J 7.1 Hz), 1.08 (3H, t, J 7.1 Hz), 0.92 (3H, d, J 6.7 Hz), 0.91 (3H,d, J 6.5 Hz ).

(b) (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B) N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester.

A stirred mixture of 2-methylimidazo[4,5-c]pyridine (3.52 g, 26 mmol),potassium hydroxide (1.48 g, 26 mmol) and tris(2-(2-methoxyethoxy)ethyl)amine (3 drops) in dry acetonitrile (200 ml)was heated at 100° C. for 3 h under argon. The temperature was reducedto 40° C. and a solution of N-4-bromomethylphenylsulphonyl-L-leucineethyl ester (10.0 g, 26 mmol) in dry acetonitrile (50 ml) was added. Themixture was stirred at 40° C. overnight. The solvent was removed and theresidue filtered through a short pad of silica (eluent: 10% methanol inDCM) to remove unreacted starting materials. Chromatography (silica: 6%methanol in DCM) gaveN-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester (regioisomer A) which eluted first followed byN-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester (regioisomer B).

Regioisomer (A) : White crystalline solid from ethyl acetate (0.58 g, 5%yield)! : m.p. 193° C. (dec.)

Analysis calculated for C₂₂ H₂₈ N₄ O₄ S; Requires C 59.44, H 6.35 N12.60; Found C 59.22, H 6.27, N 12.56.

i.r. (CHCl₃) 3015, 1735, 1420, 1185 cm⁻¹

delta_(H) 8.71 (1H, s), 8.30 (1H, d, J 5.6 Hz), 7.76 (2H, d, J 8.4 Hz),7.60 (1H, d, J 5.5 Hz), 7.30 (2H, d, J 8.4 Hz), 5.66 (2H, s), 3.82-3.74(1H, m), 3.59 (2H, q, J 7.2 Hz), 2.65 (3H, s), 1.90-1.74 (1H, m),1.43-1.31 (2H, m), 0.88 (3H, t, J 7.0 Hz), 0.82 (3H, d, J 6.7 Hz), 0.75(3H, d, J 6.5 Hz).

Regioisomer (B): White crystalline solid from ethyl acetate (0.59 g, 5%yield): m.p. 173° C. (dec.)

Analysis calculated for C₂₂ H₂₈ N₄ O₄ S; Requires C 59.44, H 6.35, N12.60; Found C 59.41, H 6.36, N 12.57.

i.r. (CHCl₃) 3005, 1735, 1415, 1170 cm⁻¹

delta_(H) 8.99 (1H, s), 8.33 (1H, d, J 5.0 Hz), 7.73 (2H, d, J 8.4 Hz),7.12-7.07 (3H, m), 6.50 (1H, d, J 9.4 Hz), 5.35 (2H, s), 3.94-3.68 (3H,m), 2.56 (3H, s), 1.72 (1H, m), 1.45 (2H, dd, J 7.4, 5.7 HE), 0.95 (3H,t, J 7.1 HE), 0.83 (3H, d, J 6.8 HE), 0.80 (3H, d, J 6.7 Hz).

EXAMPLES 36-47

The compounds of Examples 36-47 were prepared by the method of Example 1Step (c) starting from the appropriateN-4-bromomethylphenylsulphonylamino acid ester and utilising2-methylimidazo[4,5-c]pyridine in lieu of 2-methylbenzimidazole and 1:3DMF/THF as solvent. The N-4-bromomethylphenylsulphonylamino acid esterswere prepared by the method of Example 1 Step (b) from the appropriateamino acid ester hydrochloride or p-toluenesulphonate salts. If notavailable commercially the amino acid ester salts were prepared from theappropriate amino acid and alcohol according to the method of Example 2Step (a).

36. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-propyl ester and (B) N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine n-propyl ester ##STR58##

Regioisomers (A) and (B) were separated by chromatography (silica: 7%methanol in DCM).

Regioisomer (B): White crystalline (4% yield for last step afterchromatography and crystallisation from ethyl acetate): m.p. 159° C.

Analysis calculated for C₂₃ H₃₀ N₄ O₄ S; Requires C 60.24, H 6.60, N12.22; Found C 60.09, H 6.62, N 12.17.

i.r. (KBr) 1735, 1150 cm⁻¹

delta_(H) 9.04 (1H, s), 8.38 (1H, d, J 5.5 Hz), 7.79 (2H, d, J 8.3 Hz),7.13 (3H, m), 5.50 (1H, d, J 9.9 Hz), 5.38 (2H, s), 3.93 (1H, m),3.75-3.61 (2H, m), 2.59 (3H, s), 1.76 (1H, m), 1.53-1.36 (4H, m),0.95-0.73 (9H, m).

37. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineallyl ester and (B) N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine allyl ester ##STR59##

Regioisomer (A): White crystalline solid (5%.yield for last step afterchromatography (silica: 8% methanol in DCM) and crystallisation fromethyl acetate): m.p. 173° C.

Analysis calculated for C₂₃ H₂₈ N₄ O₄ S. 0.4H₂ O; Requires C 59.57, H6.26, N 12.08; Found C 59.87, H 6.16, N 11.95.

i.r. (KBr) 1740 cm⁻¹

delta_(H) 8.62 (1H, s), 8.46 (1H, d, J 5.3 Hz), 7.82 (2H, d, J 8.4 Hz),7.6 (1H, d, J 5.6 Hz), 7.14 (2H, d, J 8.3 Hz), 5.73-5.58 (1H, m), 5.46(2H, s), 5.35-5.25 (1H, m), 5.21-5.08 (2H, m), 4.26 (2H, t, J 6.8 Hz),3.96 (1H, m), 2.62 (3H, s), 1.85-1.65 (1H) 1.50 (2H, t, J 7.2 Hz), 0.83(3H, d, J 6.6 Hz), 0.74 (3H, d, J 6.8 Hz).

Regioisomer (B) : White crystalline solid from ethyl acetate (5% yield):m.p. 158° C.

Analysis calculated for C₂₃ H₂₈ N₄ O₄ S.0.2H₂ O; Requires C 60.03 H6.22,N 12.18; Found C 60.04, H 6.19, N 12.08.

i.r. (KBr) 1735, 1150 cm⁻¹

delta_(H) 9.02 (1H, s), 8.36 (1H, d, J 4.8 Hz), 7.76 (2H, d, J 8.3 Hz),7.11 (3H, m), 6.21 (1H, s), 5.70-5.55 (1H,. m), 5.37 (2H, s), 5.16-5.09(2H, m), 4.23 (2H, t, J 5.6 Hz), 3.95 (1H, m), 2.58 (3H, s), 1.74 (1H,m), 1.48 (2H, t, J 7.0 Hz), 0.85 (3H, d, J 6.6 Hz), 0.81 (3H, d, J 6.5Hz).

38. (A) N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine i-propyl ester and (B)N-4-(1H-2-methylimidazo [4,5! -c]pyridylmethyl)phenylsulphonyl-L-leucinei-propyl ester ##STR60##

Regioisomer (A) : White crystalline solid (4% yield for last step afterchromatography (silica: 4% methanol in DCM) ): m.p. 194°-195° C.

i.r. (CDCl₃) 2970, 1730, 1340, 1165 cm⁻¹

delta_(H) 8.66! ! (1H, s), 8.45 (1}I, s), 7.82 (2H, d, J 8.4 Hz), 7.67(1H, d, J 5.6 Hz), 7.18 (2H, d, J 8.4 Hz), 5.46 (2H, s), 5.35 (1H, d, J9.9 Hz), 4.63 (1H, m), 3.88 (1H, m), 2.61 (3H, s), 1.78 (1H, m), 1.45(2H, t, J 7.1 Hz), 1.05 (3H, d, J 6.3 Hz), 0.90 (3H, d, J 6.3 Hz), 0.89(3H, d, J 6.3 Hz), 0.87 (3H, d, J 6.3 Hz).

delta_(C) 171.58, 154.99, 147.88, 142.37, 140.46, 139.87, 132.13,128.16, 126.98, 114.16, 69.26, 54.51, 46.99, 42.29, 24.26, 22.69, 21.32,13.91.

Regioisomer (B) : White crystalline solid (4% yield): m.p. 172° C.

Analysis calculated for C₂₃ H₃₀ N4SO₄.0.2H₂ O; Requires C 59.77, H 6.63,N 12.12;

Found C 59.85, H 6.72, N 11.76.

i.r. (CHCl₃) 3020, 1740, 1350, 1230 cm⁻¹

delta_(H) 9.03 (1H, s), 8.38 (1H, d, J 5.5 Hz), 7.79 (2H, d, J 8.3 Hz),7.15-7.11 (3H, m), 6.31 (1H, d, J 6.9 Hz), 5.37 (2H, s), 4.59 (1H, m), 386 (1H, m), 2.58 (3H, s), 1.77 (1H, m), 1.44 (2H, t, J 7.1 Hz), 1.03(3H, d, J 6.3 Hz), 0.89-0.84 (9H, m).

39. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester and (B) N-4-(1H-2-methylimidazo[4,51-c]pyridylmethyl)phenylsulphonyl-L-leucine n-butyl ester ##STR61##

Regioisomer (A): White crystalline solid (2% yield for last step afterchromatography (silica: 4% methanol in DCM) and crystallisation fromethyl acetate):

delta_(H) 8.68 (1H, s), 8.43 (1H, s), 7.78 (2H, d, J 8.2 Hz), 7.65 (1H,m), 7.15 (2H, d, J 8.2 Hz), 5.89 (1H, d, J, 9.3 Hz), 5.47 (2H, s),3.95-3.64 (3H, m), 2.61 (3H, s), 1.75-1.65 (1H, m), 1.53-1.34 (4H, m),1.28-1.14 (2H, m), 0.98-0.78 (9H, m).

Regioisomer (B): White crystalline solid from ethyl acetate (2% yield):

delta_(H) 9.05 1H, s), 8.39 (1H, s), 7.79 (2H, d, J 8.2 Hz), 7.18-7.11(3H, m) 5.75 (1H, s), 5.38 (2H, s), 3.91 (1H, m), 3.64-3.62 (2H, m), 2 .5 (3H, s), 1.74 (1H, m), 1.50-1.34 (4H, m), 1.27-1.14 (2H, m), 0.8 -0.65(9H, m).

40. (A)-N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine1-methylpropyl ester and (B) N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine 1-methylpropyl ester##STR62##

Regioisomer (A): White crystalline solid (1.5% yield for last step afterchromatography (silica: 8% methanol in DCM) and crystallisation fromethyl acetate): m.p. 130° C.

Analysis calculated for C₂₄ H₃₂ N₄ O₄ S; Requires C 60.99, H 6.83, N11.86; Found C 60.75, H 6.80, N 11.95.

i.r. (KBr) 1735 cm⁻¹

delta_(H) 8.62 (1H, s), 8.47 (1H, d, J 5.6 Hz), 7.83 (2H, d, J 7.2 Hz),7.66 (1H, d, J 5.7 Hz), 7.19 (2H, d, J 6.9 Hz), 5.45 (2H, s), 5.16 (1H,m), 4.52 (1H, m), 3.89 (1H, m), 2.61 (3H, s), 1.84-1.63 (1H, m),1.50-1.26 (4H, m), 1.04-0.61 (12H, m).

Regioisomer (B): White crystalline solid from ethyl acetate (1% yield):m.p. 165° C.

Analysis calculated for C₂₄ H₃₂ N₄ O₄ S.0.2H₂ O; Requires C 60.53, H6.86, N 11.77; Found C 60.66, H 6.78, N 11.73.

i.r. (KBr) 1730, 1320, 1145 cm⁻¹

delta_(H) 9.00 (1H, s), 8.33 (1H, d, J 5.5 Hz), 7.73 (2H, d, J 8.3 Hz),7.09 (3H, m), 6247 (1H, d, J 8.2 Hz), 5.34 (2H, s), 4.45 (1H, m), 3.85(1H, m), 2.54 (3H, s), 1.74 (1H, m), 1.50-1.19 (4H, m), 0.98-0.57 (12H,m).

41. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester and (B)N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester ##STR63##

Regioisomer (A) : Yellow crystalline solid (4% yield for last step afterchromatography (silica: 5% methanol in DCM)): m.p. 108°-110° C.

Analysis calculated for C₂₇ H₃₀ N4SO₄.0.4H₂ O; Requires C! 63.11H 6.04,N 10.90; Found C 63.18, H 5.99, N 10.84.

i.r. (CHCl₃) 2960, 1740, 1340, 1170 cm⁻¹

delta_(H) 8.61 (1H, s), 8.40 (1H, d, J 5.1 Hz), 7.74 (2H, d, J 8.4 Hz),7.61 (1H, d, J 5.4 Hz), 7.32-7.20 (3H, m), 7.14-7.07 (4H, m), 6.31 (1H,d, J 8.4 Hz), 5.38 (2H, s), 4.83 (1H, d, J 12.a Hz), 4.76 (1H, d, J 12.4Hz), 4.00 (1H, m), 2.57 (3H, s), 1.72 (1H, m), 1.48 (2H, t, J 7.1 Hz),0.83 (3H, d, J 6.8 Hz), 0.80 (3H, d, J 6.7 Hz).

Regioisomer (B): White crystalline solid (4% yield): m.p. 180°-181° C.

Analysis calculated for C₂₇ H₃₀ N₄ SO₄.0.2H₂ O; Requires C 63.34, H6.02, N 10.94; Found C 63.42, H 5.98, N 10.95.

i.r. (CHCl₃) 2960, 1740,.1340, 1140 cm⁻¹

delta_(H) 9.03 (1H, s),. 8.36 (1H, d, J 5.1 Hz), 7.78 (2H, d, J 8.5 Hz),7.34-7.26 (3H, m), 7.19-7.13 (3H, m), 7.12 (2H, d, J 8.4 Hz), 5.52 (1H,d, J 9.9 Hz), 5.35 (2H, s), 4.84 (1H, d, J 12.3 Hz), 4.78 (1H, d, J 12.2HZ), 4.00 (1H, dr, J 9.8, 7.3 Hz), 2.57 (3H, S), 1.74 (1H, m), 1.49 (2H,t, J 7.1 Hz), 0.86 (3H, d, J 6.6 Hz), 0.83 (3H, d, J 6.5 Hz).

42. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-ethoxyethyl ester and (B)N-4-(1H-2methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-ethoxyethyl ester ##STR64##

Regioisomer (A): Yellow crys=alline solid (8% yield for iasc step afterchromatography (silica: 6% methanol in DCM)): m.p. 98° C.

Analysis calculated for C₂₄ H₃₂ N₄ O₅ S.0.8H₂ O; Requires C 57.31H 6.73,N 11.14; Found C 57.30, H 6.46, N 10.97.

delta_(H) 8.80 (1H, s), 8.60 (1H, s), 7.78 (2H, d, J 8.3 Hz), 7.69 (1H,d, J 4.8 Hz), 7.18 (2H, d, J 8.4 Hz), 6.12 (1H, d, J 9.7 Hz), 5.51 (2H,s), 4.00-3.87 (2H, m), 3.78 (1H, m), 3.44-3.30 (4H, m), 2.63 (3H,, s),1.77 (1H, m), 1.49 (2H, =, J 7.1 Hz), 1.11 (3H, t, J 7.0 Hz); 0.86 (3H,d, J 6.6 Hz), 0.82 (3H, d, J 6.5 Hz).

Regioisomer (B) : White crystalline solid (8% yield): m.p. 176° C.

Analysis calculated for C₂₄ H₃₂ N₄ O₅ S1.0H₂ O; Requires C 56.90, H6.76, N 11.06; Found C 56.63, H 6.38, N 10.86.

i.r. (CHCl₃) 3010, 1725, 1340, 1100 cm⁻¹

delta_(H) 9.02 (1H, s), 8.37 (1H, d, J 4.6 Hz), 7.77 (2H, d, J 8.4 Hz),7.17-7.11 (3H, m), 5.98 (1H, d, J 9.8 Hz), 5.38 (2H, s), 4.00-3.84 (2H,m), 3.74 (1H, m), 3.43-3.30 (4H, m), 2.58 (3H, s), 1.75 (1H, m), 1.48(2H, t, J 7.1 Hz), 1.10 (3H, t, J 7 . 0 Hz), 0.86 (3H, d, J 6.7 Hz),0.82 (3H, d, J 6.5 Hz).

43. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-benzoxyethyl ester and (B) N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine 2-benzoxyethyl ester##STR65##

Regioisomers (A) and (B) were separated by chromatography (silica: 5%methanol in DCM).

Regioisomer (B): Colourless oil (2% yield for last step afterchromarotgraphy).

i.r. (CDCl₃) 2960, 1735, 1340, 1155 cm⁻¹

delta_(H) 9.05 (1H, s), 8.37 (1H, d, J 5.5 Hz), 7.75 (2H, d, J 8.3 Hz),7.40-7.25 (5H, m), 7.14-7.04 (3H, m), 5.32 (2H, s), 5.15 (1H, br d, J9.7 Hz), 4.43 (2H, dd, J 13.0, 12.2 Hz), 4.04-3.73 (3H, m), 3.50-3.36(2H, m), 2.57 (3H, s), 1.78-1.62 (1H, m), 1.60-1.42 (2H, m)/0.88 (3H, d,J 6.7 Hz), 0.86 (3H, d, J 6.7 Hz).

delta_(C) 172.00, 153.21, 145.52, 142.15, 140.04, 139.90, 137.60,132.25, 128.49, 128.19, 127.92, 127.71, 126.69, 104.61, 73.11, 67.35,64.43, 54.46, 46.84, 42.27, 24.28, 22.68, 21.34.

44. (A)N-4-(3H-2-Methylimidazo[4,5c]Pyridylmethyl)phenylsulphonyl-L-leucine1-methyl-2-methoxyethyl ester and (B)N-4-(1H-2-methylimidaizo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine1-methyl-2-methoxyethyl ester ##STR66##

Regioisomers (A) and (B) were separated by chromatography (silica: 6%methanol in DCM).

Regioisomer (B): White crystalline solid (2% yield for last step afterchromatography): m.p. 148°-150° C.

Analysis calculated for C₂₄ H₃₂ N₄ SO₅ ; Requires C 58.99, H 6.61, N11.47; Found C 58.95, H 6.71, N 11.06.

i.r. (CHCl₃).3015, 1735, 1340, 1115 cm⁻¹

delta_(H) 9.02 (1H, s), 8.37 (1H, d, J 5.5 Hz), 7.80-7.75 (2H, m), 7.12(3H, br d, J 7.9 Hz), 5.83 (0.5H, d, J 9.4 Hz), 5.74 (0.5H, d, J 9.8Hz), 5.36 (2H, s), 4.71 (0.5H, m), 4.59 (0.SH, m), 3.92 (1H, m), 3.24(3H, s), 3.19-3.06 (2H, m), 2.58 (3H, s), 1.78 (1H, m), 1.48 (2H, t, J7.1 Hz), 0.98 (1.5H, d, J 6.4 Hz), 0.89-0.84 (7.5H, m).

45. (A) N-4-!(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-(2-ethoxyethoxy) ethyl ester and (B)N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine2-(2-ethoxyethoxy)ethyl ester ##STR67##

Regioisomer (A): Colourless oil (2% yield for last step afterchromatography (silica: 4% methanol in DCM)).

i.r. (CHCl₃) 2080, 1735, 1340, 1160 cm⁻¹

delta_(H) 8.62 (1H, s), 8.44 (1H, d, J 5.5 Hz), 7.82 (2H, d, J 8.5 Hz),7.64 (1H, d, J 5.5 Hz), 7.20 (2H, d, J 8.5 Hz), 5.46 (2H, s), 5.41 (1H,br s), 3.98-3.75 (3H, m), 3.53-3.38 (SH, m), 2.62 (3H, s), 1.77 (11H,m), 1.49 (2H, t, J 7.1 Hz), 1.18 (3H, t, J 7.0 Hz), 0.88 (3H, d, J 7.1Hz), 0.86 (3H, d, J 7.0 Hz).

delta_(C) 171i96, 155.03, 147.89, 142.38, 140.28, 139.85, 132.99,132.27, 128.17, 126.92, 114.12, 70.44, 69.64, 68.39, 66.60, 64.31,63.60, 54.48, 42.11, 24.26, 22.65, 21.33, 15.10, 13.94.

Regioisomer (B) : White crystalline solid (1% yield).

delta_(H) 9.05i (1H, s), 8.39 (1H, d, J 5.4 Hz), 7.81 (2H, d, J 8.4 Hz),7.19-7i. 15 (3H, m), 5.40 (2H, s), 5.34 (1H, d, J 10.0 Hz), 4.01-3.74(3H, m), 3.64-3.44 (8H, m), 2.60 (3H, s), 1.77 (1H, m), 1.49 (2H, t,i J7.1 Hz), 1.19 (3H, t, J 7.0 Hz), 0.88 (3H, d, J 6.6 Hz), 0.86 (3H, d, J6.6 Hz).

delta_(C) 172.i07, 153.54, 142.09, 142.02, 140.36, 140.26, 139.99,128.15, 127.03, 104.83, 71.70, 70.62, 70.39, 69.78, 68.49, 66.74, 64.45,54.62, 47.01, 42.29, 24.38, 22.78, 21.47, 15.24, 14.09.

46. (A)N-4i-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycineethyl ester and (B) N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D, L-allylglycine ethyl ester##STR68##

Regioisomer (A): Colourless oil (1.5% yield for last step afterchromatography (silica: 2% methanol in DCM))

delta_(H) 8.62 (1H, s), 8.44 (1H, d, J 5.4 Hz), 7.80 (2H, d, J 8.1 Hz),7.64 (1H, d, J 5.4 Hz), 7.17 (2H, d, J 8.1 Hz), 5.80-5.50 (2H, m), 5,45(2H, s), 5.15-5.00 (2H, m), 4.20-3.80 (3H, m), 2.61 (3H, s), 2.46 (2H,t, J 6.5 Hz), 1.06 (3H, t, J 7.0 Hz).

Regioisomer (B) : White crystalline solid (0.4% yield): m.p. 138° C.

i.r. (CDCl₃) 1735, 1340, 1160 cm⁻¹

delta_(H) 9.05 (1H, s), 8.39 (1H, d, J 5.6 Hz), 7.80 (2H, d, J 8.2 Hz),7.23-7.04 (3H, m), 5.70-5.45 (4H, m), 5.15-5.00 (2H, m), 4.10-3.80 (3H,m), 2.60 (3H, s), 2.47 (2H, t, J 6.3 Hz), 1.07 (3H, t, J 7.0 Hz).

47. (A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-methionineethyl ester and (B)N-4-(1H-2methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-methionineethyl ester ##STR69##

Regioisomer (A) : Yellow crystalline solid (6% yield for last step afterchromatography (silica: 5% methanol in DCM)):m.p. 187°-189° C.

Analysis calculated for C₂₁ H₂₆ N₄ O₄ S₂.1.0H₂ O; Requires C 52.48, H5.87, N 11.66; Found C 52.50, H 5.50, N 11.29.

i.r. (CHCl₃) 3015, 1735, 1350, 1160 cm⁻¹

delta_(H) 8.62 (1H, s), 8.43 (1H, d, J 5.5 Hz), 7.78 (2H, d, J 8.4 Hz),7.63 (1H, d, J 5.3 Hz), 7.16 (2H, d, J 8.4 Hz), 6.27 (1H, s), 5.44 (2H,s), 4.05 (1H, br s), 3.95-3.81 (2H, m), 2.60 (3H, s), 2.59-2.42 (2H, m),2.01 (3H, s), 1.99-1.82 (2H, m), 1.02 (3H, t, J 7.2 Hz).

Regioisomer (B): Yellow crystalline solid (6% yield): m.p. 137°-138° C.

Analysis calculated for C₂₁ H₂₆ N₄ O₄ S₂ ; Requires C 53.69, H 5.75, N11.93; Found C 53.70, H 5.63, N 11.79.

i.r. (CHCl₃) 3020, 1730, 1330, 1180 cm⁻¹

delta_(H) 9.06 (1H, s), 8.40 (1H, s), 7.83 (2H, d, J 8.4 Hz), 7.19-7.13(3H, m), 5.48 (1H, d, J 9.0 Hz), 5.39 (2H, s), 4.06 (1H, m), 3.98-3.81(2H, m), .2.60 (3H, s), 2.57-2.43 (2H, m), 2.05 (3H, s), 2.01-1.77 (2H,m), 1.06 (3H, t, J 7.1 Hz).

EXAMPLE 48

(A)N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester and (B)N-4-(1H-2-methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester ##STR70##

(a) 2-Methyl-5-fluorobenzimidazole

Ethyl acetimidate hydrochloride (37.1 g, 0.3 mol) was added to a stirredsuspension of 4-fluoro-ortho-phenylenediamine (12.6 g, 0.1 mol) inethanol (150 ml) at 0° C. The mixture was allowed to warm up to roomtemperature and stirred overnight. The solvent was removed under,reduced pressure and the residue extracted into ethyl acetate (100 ml),washed with water (3×100 ml), dried over anhydrous magnesium sulphate,filtered and evaporated. Crystallisation from ethyl acetate gave2-methyl-5-fluorobenzimidazole (7.7 g, 51%) as a brown crystallinesolid.

m.p. 177°-178° C.

delta_(H) 7.46 (1H, dd, J 8.8, 4.7 Hz), 7.22 (1H, dd, J 8.9, 2.4 Hz),6.98 (1H, ddd, J 9.7, 8.9, 2.4 Hz), 2.65 (3H, s).

(b)N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester and N-4-(1H-2-methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester

N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester (A) andN-4-(1H-2-methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester (B) were prepared by the method of Example 7.employing2-methyl-5-fluorobenzimidazole in lieu of 2-methylbenzimidazole in thefinal step.

Regioisomers (A) and (B) were obtained as a mixture.

White crystalline solid (2% yield for last step after chromatography(silica: 4% methanol in DCM) and crystallisation from ethyl acetate):m.p. 196°-197° C.

Analysis calculated for C₂₂ H₂₆ FN₃ O₄ S; Requires C 59.04, H 5.86, N9.39; Found C 5 9.19, H 5.90, N 9.39.

delta_(H) (CD3OD) 7.74 (2H, dd, J 8.3, 1.6 HZ), 7.52 (0.6H, dd, J 8.8,4.7 Hz), 7.35-7.22 (2.8H, m), 7.13 (0.6H, dd, J 8.9, 2.4 Hz), 6.97 (1H,m), 5.54 (0.8H, s), 5.51 (1.2H, s), 3.80 (1H, m), 3.23 (1.8H, s), 3.22(1.2H, s), 2.55 (1.2H, S), 2.54 (1.8H, s), 1.60 (1H, m), 1.43-1.34 (2H,m), 0.82 (3H, d, J 6.6 Hz), 0.74 (3H, d, J 6.6 Hz).

EXAMPLE 49

(A)N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-4-(1H-2-methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR71##

(A)N-4-(1H-2-Methyl-5-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-4-(1H-2-methyl-6-fluorobenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester were prepared by the method of Example 48 starting fromL-leucine ethyl ester hydrochloride.

Regioisomers (A) and (B) were obtained as a 1:1 mixture.

White crystalline solid (14% yield for last step after chromatography(silica: 4% methanol in DCM)): m.p. 159°-161° C.

Analysis calculated for C₂₃ H₂₈ FN₃₀₄ S.0.2H₂ O; Requires C 59.39, H6.15, N 9.03; Found C 59.36, H 6.11, N 9.01.

i.r. (CDCl₃) 2960, 1740, 1350, 1160 cm⁻¹

delta_(H) 7.79 (2H, dd, J 8.3, 1.5 Hz), 7.65 (0.5H, dd, J 8.8, 4.8 Hz),7.41 (0.5H, dd, J 9.3, 2.3 Hz), 7.15 (2H, d, J 8.3 Hz), 7.07-6.91 (1.5H,m), 6.81 (0.SH, dd, J 8.5, 2.4 Hz), 5.36 (1H, s), 5.33 (1H, s), 5.15(1H, m), 3.95-3.71 (3H, m), 2.57 (1.5H, s), 2.56 (1.5H, s), 1.77 (1H,m), 1.47 (2H, t, J 7.1 Hz), 1.03-0.97 (3H, m), 0.89 (3H, d, J 6.8 Hz),0.86 (3H, d, J 6.7 Hz).

EXAMPLE 50N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane##STR72## (a) N-Acetyl-2-keto-3-amino-4-methylpentane

A mixture of L-valine (25.0 g, 0.21 mol), acetic anhydride (60.5 ml,0.64 mo ), pyridine (52 ml, 0.64 mol) and 4-dimethylaminopyridine (2.0g, 16.6 mmol) was heated at reflux overnight. The reaction mixture wasallowed to cool to room temperature and methanol added with rapidstirring. The mixture was concentrated under reduced pressure to give anoil .which.was dissolved in diethyl ether (250 ml), washed with 2Mhydrochloric acid (150 ml), saturated aqueous sodium hydrogen carbonate(150 ml) and brine (150 ml) dried over anhydrous magnesium sulphate,filtered and evaporated. Distillation under reduced pressure gaveN-acetyl-2-keto-3-amino-4-methylpentane (6.3 g, 19%) as a viscous strawcoloured oil (76-78° C. @1.5 mmHg).

delta_(H) 6.92 /(1H, br d), 4.41 (1H, dd), 2.09 (1H, m), 2.03 (3H, s),1.84 (3H, s)_(I) -0.80 (3H, d), 0.64 (3H, d).

(b) 2-Keto-3-amino-4-methylpentane hydrochloride

A mixture of N-acetyl-2-keto-3-amino-4-methylpentane (6.33 g, 40.3 mmol)and 6]hydrochloric acid (65 ml) was heated at reflux overnight. Thereaction mixture was cooled to room temperature, ethanol (100 ml) wasadded and the mixture concentrated under reduced pressure. The mixturewas triturated with ether to give a precipitate which was collected byfiltration. Crystallisation from acetone gave2-keto-3-amino-4-methylpentane hydrochloride (2.9 g, 63%) as a whitecrystalline solid.

mp. 134°-135° C.

delta_(H) 8.41 (3H, br s), 4.01 (1H, m), 3.72 (br s), 2.34 (1H, m), 2.24(3H, s), 1.02 (3H, d), 0.87 (3H, s).

(c)N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane

N-4-(1H-2-Methylbenzimidazolylmethyl)phenylsulphonyl-2-keto-3-amino-5-methylhexanewas prepared by the method of Example 1 Step (b) and Step (c) startingfrom 2-keto-3-amino-4-methylpentane hydrochloride.

White crystalline solid (5% yield for last step after chromatography(silica: 5% methanol in DCM)): m.p. 140° C.

i.r. (CDCl₃) 1720, 1345, 1160 cm⁻¹

delta_(H) 7.72-7.62 (3H, m), 7.30-7.00 (5H, m), 5.76 (1H, d, J 8.8 Hz),5.30 (2H, s), 3.75 (1H, dd, J 8.8, 3.8 Hz), 2.50 (3H, s), 2.12-2.00 (1H,m), 1.90 (3H, s), 0.95 (3H, d, J 6.7 Hz), 0.65 (3H, d, J 6.7 Hz).

delta_(C) 2.05.41, 151.56, 142.48, 140.89, 139.51, 134.99, 127.77,126.74, 122.42, 122.20, 119.19, 109.00, 66.95, 46.50, 29.82, 27.29,19.74, 16.05.

EXAMPLE 51

(A)N-4-(3H-2-Methylimidazo[4,5c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentaneand (B)N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-ket0-3-amino-4-methylpentane##STR73##

(A)N-4-(3H-2-Methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentaneand (B) N-4-(1H-2-methylimidazo [4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane were prepared by the method of Example 50employing 2-methylimidazo[4,5-c]pyridine in lieu of2-methylbenzimidazole in the final step and obtained as a 1:1 mixture ofregioisomers (A) and (B).

Orange viscous oil (4% yield for last step after chromatography (silica:5% methanol in DCM)).

i.r. (CDCl₃) 1720, 1340, 1160 cm⁻¹

delta_(H) 9.04 (0.5H, br s), 8.58 (0.5H, br s), 8.45 (0.5H, br d), 8.39(0.5H, br d), 7.78 (2H, m), 7.20-7.07 (3H, m), 5.49-5.37 (3H, m),3.89-3.77 (1H, m), 2.60 (1.SH, s), 2.57(1.5H, s), 2.20-2.06 (1H, m),1.94 (1.5H, s), 1.92 (1.5H, s), 1.04 (3H, dd), 0.70 (3H, d).

EXAMPLE 52N-Methyl-N-4-(1H-2-methylbenzimidazolylmethyl)phenylsulphonyl-L-leucinemethyl ester ##STR74##

To a stirred solution of4-(2-methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine methyl ester(0.94 g, 2.2 mmol) in dry THF (50 ml) was added sodium hydride (60%dispersion in oil; 96 mg, 2.4 mmol) at room temperature under argon.After 1 h methyl iodide (0.41 ml, 6.6 mmol) was added and the reactionmixture stirred at room temperature overnight. The solvent was removedunder reduced pressure and the residue extracted into ethyl acetate (100ml), washed with water (100 ml) and brine (100 ml), dried over anhydrousmagnesium sulphate, filtered and evaporated. Chromatography (silica: 4%methanol in DCM) gave N-methyl-N-4-(1H-2-methylbenzimidazolylmethyl)phenylsulphonyl-L-leucine methyl ester(220 mg, 23%) as a white crystalline solid.

m.p. 149° C.

Analysis calculated for C₂₃ H₂₉ N₃₀₄ S.0.2H₂ O; Requires C 61.78, H6.63, N 9.40; Found C 61.76, H 6.62, N 9.33.

i.r. (CHCl₃) 3010, 1730, 1340, 1150 cm⁻¹

delta_(H) 7.68-7.62 (3H, m), 7.21-7.06 (5H, m), 5.27 (2H, s), 4.57 (1H,m), 3.28 (3H, s), 2.76 (3H, s), 2.48 (3H, s), 1.55-1.52 (3H, m),0.89-0.86 (6H, m).

EXAMPLE 53

(A)N-MethyI-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B) N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester ##STR75##

(a) N-Methyl-N-4-bromomethylphenylsulphonyl-L-leucine ethyl ester

N-4-Bromomethylphenylsulphonyl-L-leucine ethyl ester (2.0 g, 5.1 mmol)was dissolved in dry THF (30 ml) under argon and cooled to 0° C. Sodiumhydride (60% dispersion in oil: 200 mg, 5.1 mmol) was added followed bymethyl iodide (0.64 ml, 10.2 mmol) after a period of 5 rains. Thereaction mixture was allowed to warm to room temperature and was stirredovernight. The reaction mixture was quenched with saturated aqueousammonium chloride (30 ml) and extracted with ethyl acetate (2×50 ml).The combined organic extracts were washed with brine (50 ml), dried overanhydrous sodium sulphate, filtered and evaporated to giveN-methyl-N-4-bromomethylphenylsulphonyl-L-leucine ethyl ester as anorange oil which was used directly in the next step without furtherpurification.

(b) (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B) N-methyl-N-4-(1H-2methyl-N-4-(1-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester

2-Methylimid.azo[4,5-c]pyridine (1.00 g, 7.5 mmol) was dissolved in dryDMF (4 ml) and the mixture diluted with dry THF (50 ml) with stirringunder argon. The solution was cooled to 0° C. and sodium hydride (60%dispersion in oil) (300 mg, 7.5 mmol) added. After 1 h a solutior. ofN-methyl-N-4-bromomethylphenylsulphonyl-L-leucine ethyl ester (3.05 g,7.5 mmol) in dry THF (10 ml) was added. The mixture was allowed to warmup to room temperature and stirred overnight. Saturated ammoniumchloride (100 ml) was added and the product extracted using DCM (3×100ml). The combined organic layers were washed with water (2×50 ml), driedover anhydrous sodium sulphiLte, filtered and the solvent removed.Chromatography (silica: 4 % methanol in DCM) gaveN-methyl-N-4-(3H-2methylimidazo [4,5-c]pyr.idylmethyl)phenylsulphonyl-L-leucine ethyl ester (regio..somer A) whicheluted first followed byN-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester (regioisomer B).

Regioisomer A) : Colourless oil (6% yield).

i.r. (CDCl₃) 2210, 1725, 1330 cm⁻¹

delta_(H) 8.41 i(1H, s),. 8.22 (1H, d, J 5.6 Hz), 7.52 (2H, d, J 8.4Hz), 7.42 (1H, d, J 6.1 Hz), 6.99 (2H, d, J 8.3 Hz), 5.28 (2H, s), 4.41(1H, t, J 6.6 Mr), 3.59 (2H, q, J 7.1 Mr), 2.62 (3H, S), 2.42 (3H, S),1.49-1.33 (3H, 4), 0.80-0.63 (9H, m).

delta_(C) 170.22, 154.70, 147.37, 141.80, 139.58, 138.64, 132.55,131.99, 127.63, 126.33, 113.50, 60.41, 56.73, 46.57, 37.56, 29.37,23.91, 22.56, 20.59, 13.48, 13.40.

Regioisomer (B) : White crystalline solid from ethyl acetate (8% yield):m.p. 105° C.

Analysis calculated for C₂₃ H₃₀ N₄ O₄ S; Requires C 60.24, H 6.60, N12.22; Found C 60.21, H 6.59, N 12.08.

i.r. (KBr) 2960, 1730, 1330, 1150 cm⁻¹

[α]_(D) ²⁰ -6.7 (c 2.0, CDCl₃)

delta_(H) 9.03 (1H, s), 8.37 (1H, d, J 5.5 Hz), 7.76 (2H, d, J 8.4 Hz),7.18-7.11 (3H, m), 5.39 (2H, s), 4.65-4.59 (1H, m), 3.83 (2H, q, J 7.1Hz), 2.82, (3H, s), 2.59 (3H, s), 1.69-1.55 (3H, m), 1.02.(3H, t, J 7.1Hz), 0.97 (3H, d, J 6.1 Hz), 0.95 (3H, d, J 6.2 Hz).

An alternative regioselective synthesis gives regioisomer (B) alone inan improved overall yield and involves the following steps.

(c) N-4-Azidomethylphenylsulphonyl-L-leucine ethyl ester

A solution of sodium azide (75.0 g, 1.054 mol) in water (150 ml) wasadded to a solution of the N-4-bromoethylphenylsulphonyl-L-leucine ethylester (89.0 g, 0.221 4ol) in dichloromethane (150 ml).Benzyltriethylammonium chloride (10 g, 0.044 mol) was added and thehererogenous reaction mixture stirred vigorously for 60 h. The organicportion was separated, washed thoroughly with water, dried overanhydrous magnesium sulphate, filtered and concentrated to a golden oil,which crystallised on standing. The resulting white solid was freezedried overnight to yield N-4-azidomethylphenylsulphonyl-L-leucine ethylester (78.2 g, 97%).

m.p. 75°-77° C.

Analysis calculated for C15H₂₂ N₄ O₄ S; Requires C 50.83, H 6.26, N15.81; Found C50.80, H 6.28, N 15.82.

i.r. (DCM) 2930, 2100, 1730, 1335, 1150 cm⁻¹

[α]_(D) ²⁵ -16.4 (c 2.0, DCM)

delta_(H) (CDCl₃) 7.86 (2H, d, J 8.4 Hz), 7.45 (2H, d, J 8.6 Hz), 5.13,(1H, d, J 10.0 Hz), 4.43 (2H, s), 3.98-3.84 (3H, m), 1.83-1.75 (1H, m),1.49 (2H, dd, J 7.7, 6.7 Hz), 1.09 (3H, t, J 7.1 Hz), 0.91 (3H, d, J 6.7Hz), 0.89 (3H, d, J 6.5 Hz).

(d) N-Methyl-N-4-azidomethylphenylsulphony.l-L-leucine ethyl ester

A 60% dispersion of sodium hydride in mineral oil (9.68 g, 0.242 mol)was added in portions to a solution ofN-4-azidomethylphenylsulphonyl-L-leucine ethyl ester (78.0 g, 0.220 mol)in THF (200 ml) at 0° C. After stirring for 20 mins iodomethane (28 ml,0.44 mol) was added slowly, and the reaction allowed to warm to ambienttemperature overnight. Saturated ammonium chloride solution (ca. 15 ml)was added and the THF removed under reduced pressure. The resultingresidue was taken up in dichloromethane, washed with saturated hydrogencarbonate solution then water, dried over anhydrous magnesium sulphate,filtered and concentrated to giveN-methyl-N-4-azidomethylphenylsulphonyl-L-leucine ethyl ester as anorange oil (76.0 g, 94%).

Analysis calculated for C₁₆ H₂₄ N₄ O₄ S; Requires C 52.16, H 6.57, N15.21; Found C 52.20, H 6.54, N 15.12.

i.r. (DCM) 2100, 1735, 1340, 1160 cm⁻¹

[α]_(D) ²⁰ -15.3 (c 2.2, DCM)

delta_(H) (CDCl₃) 7.83 (2H, dd, J 8.2, 1.6 Hz), 7.45 (2H, d, J 8.3 Hz),4.71-4.65 (1H, m), 4.44 (2H, s), 3.96-3.86 (2H, m), 2.86 (3H, s),1.67-1i58 (3H, m), 1.09 (3H, t, J 7.1 Hz), 0.99 (3H, d, J 5.0 Hz), 0.97(3H, d, J 6.1 Hz).

(e) N-Methyl-N-4-aminomethylphenylsulphonyl-L-leucine ethyl ester

Triphenylphosphine (101.80 g, 0.388 mol) was added to a solution ofN-methyl-N-4-azidomethylphenylsulphonyl-L-leucine ethyl ester (71.5 g,0.194 mol) in a mixture of THF and water (4:1, 200 ml), and the reactionmixture stirred overnight at ambient temperature. The THF was removedunder reduced pressure, and the product extracted With ethyl acetate,dried over anhydrous magnesium sulphate, tiltered and concentrated to anorange oil. This was purified byichromatography over silica (1:2EtOAc--hexane; EtOAc; 10% MeOH-EtOAc) to giveN-methyl-N-4-aminomethylphenylsulphonyl-L-leucine ethyl ester (38 g,58%) as a yellow oil.

delta_(H) (CDCl₃) 7.76 (2H, dd, J 8.5, 1.7 Hz), 7.45 (2H, d, J 8.3 Hz),4.71-4i65 (1H, m), 3.95 (2H, s), 3.95-3.85 (2H, m), 2.83 (3H, s), 1.95(2H, br s), 1.68-1.57 (3H, m), 1.06 (3H, t, J 7.1 Hz), 0.97 (3H, d,l J5.4 Hz), 0.95 (3H, d, J 5.9 Hz).

(f) N-Methyl-N-4-(N'-3-nitropyrid-4-yl)aminomethylphenylsulphonyl-L-leucine ethyl ester

4-Chloro-3-nitropyridine (6.0 g, 38 mmol) was added to a stirredsolution of N-methyl-N-4 -aminomethylphenylsulphonyl-L-leucine ethylester (13.0 g, 38 mmol) and triethylamine (5.3 ml, 38 mmol) inchloroform (150 ml ) at ambient temperature. The react ion mixture wasistirred for 60 h, then washed with water, dried over anhydrousmagnesium sulphate, filtered and the solvent removed under reducedpressure to leave a brown oil. This was purified by chromatography oversilica (gradient elution 33% EtOAC-hexane, EtOAC) to giveN-methyl-N-4-(N'-3-nitropyrid-4-yl)aminomethylphenylsulphonyl-L-leucineethyl ester (10.9 g, 62%) as a yellow amorphous solid.

m.p. 71°-75° C.

i.r. (DCM) 3390, 1730, 1510, 1330 cm⁻¹

[α]_(D) ²⁵ -13.8 (c 2.0, DCM)

delta_(H) (CDCl₃) 9.00 (1H, s) 8.55 (1H, t, J 5.9 Hz), 8.04 (1H, d, J6.1 Hz), 7.60 (2H, d, J 8.3 Hz), 7.32 (2H, d, J 8.3 Hz), 6.50 (1H, d, J6.2 Mr), 4.57 (2H, d, J 5.9 Hz), 4.50-4.44 (1H, m), 3.75-3.62 (2H, m),2,69 (3H, s), 1.45 (3H, br d), 0.86 (3H, t, J 7.1 Hz) 0.77 (6H, 6, J 5.9Hz).

(g) N-Methyl-N-4-(N'-3-aminopyrid-4-yl)aminomethylphenylsulphonyl-L-leucine ethyl ester

A solution ofN-methyl-N-4-(N'-3.-nitropyrid-4-yl)aminomethylphenylsulphonyl-L-leucineethyl ester (10.9 g, 0.023 mol) in ethanol (40 ml) was hydrogenated at100 p.s.i. overnight in the presence of 10% palladium on charcoal (1.0g). The catalyst was removed by Filtration through GF/F filter paper,and the filtrate evaporated under reduced pressure to giveN-methyl-N-4-(N'-3-aminopyrid-4-yl) aminomethylphenylsulphonyl-L-leucineethyl ester (8.90 g, 87 % ) as a brown foam.

delta_(H) (CDCl₃) 7.86 (1H, s) 7.83 (1H, s, J 5.5 Hz), 7.73 (2H, d, J8.3 Hz), 7.41 (2H, d, J 8.3 Hz), 6.29 (1H, d, J 5.4 Hz), 5.04 (1H, m),4.67-4.61 (1H, m), 4.44 (2H, d, J 5.6 Hz), 3.90-3.81 (2H, m), 2.84 (3H,s)i, 1.62-1.57 (5H, m), 1.04 (3H, t, J 7.1 Hz), 0.96 (3H, d, J 6.0 Hz)i,0.95 (3H, d, J 6.1 Hz).

(h)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester

N-Methyl-N-4-(N'-3-aminopyrid-4-yl)aminomethylphenylsulphonyl-L-leucineethyl ester (8.90 g, 20.5 mmol) was refluxed overnight in aceticanhydride (90 ml). The reaction mixture was allowed to cool, thenmethanol added cautiously until effervescenee ceased. The volatiles wereremoved under reduced pressure and the residue partitioned betweensaturated sodium hydrogen carbonate solution and ethyl acetate. Theorganic portion was washed with saturated sodium hydrogen carbonate(×3), and water, dried over anhydrous sodium sulphate, filtered andconcentrated to a brown oil. This was passed down a pad of silica (3%methanol in DCM) to remove baseline material, and the produce furtherpurified by medium pressure liquid chromatography (silica gel: 3%methanol in DCM plus traceof triethylamine) to give a pale yellow oil(5.12 g, 55%), whichl solidified slowly on standing. Recrystallisationfrom ethyl acetate/DIPE gaveN-methyl-N-4-(1H-2-methylimidazo[4,5c]pyridylmeithyl)phenyl-sulphonyl-L-leucineethyl ester as a white solid identical to that obtained above in step(b).

EXAMPLE 54N-Methyl-N-4-(1H-2-methylbenzimidazolylmethy1)phenylsulphonyl-L-leucineethyl ester ##STR76##

N-Methyl-N-4-(1H-2-methylbenzimidazolylmethyl)phenylsulphonyl-L-leucineethyl ester was prepared by the method of Example 53 Steps (a) and (b)employing 2-methylbenzimidazole in lieu of2-methylimidazo[4,5-c]pyridine in Step (b).

White crystalline solid (22% yield for last step after chromatography(silica: 6% methanol in DCM)): m.p. 104° C.

Analysis calculated for C₂₄ H₃₁ N₃ O₄ S; Requires C 63.00, H 6.83, N9.18, S 7.01; Found C =62.87, H 6.81N 9.04, S 7.13.

i.r. (CHCl₃) 1760, 1340, 1145 cm⁻¹

delta_(H) 7.73 (3H, m,), 7.31-7.14 (SH, m), 5.39 (2H, s), 4.66-4.60 (1H,m), 3.80 (2H, q, J 7.1 Hz), 2.83 (3H, s), 2.58 (3H, s), 1.70-1.54 (3H,m), 1.01-0.93 (9H, m).

EXAMPLE 55

(A)N-Methyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-methyl-N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR77##

(A)N-Methyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-methyl-N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester were prepared by the method of Example 53 Steps (a) and (b)employing imidazo[4,5-c]pyridine in lieu of2-methylimidazo[4,5-c]pyridine in Step (b).

Regioisomer (A): White crystalline solid (7% yield for last step afterchromatography (silica: 5% methanol in DCM)): m.p. 94° C.

Analysis calculated for C₂₂ H₂₈ N₄ O₄ S.0.9H₂ O; Requires C 57.35, H6.52, N 12.16, S 6.96; Found C 57.42, H 6.16, N 11.83, S 7.04.

i.r. (CHCl₃) 1730, 1335, 1150 cm⁻¹

delta_(H) 8.58 (1H, s,), 8.34 (1H, d, J 5.6 Hz), 8.06 (1H, s), 7.66-7.58(3H, m), 7.19 (2H, d, J 8.4 Hz), 5.44 (2H, s), 4.55-4.46 (1H, , m), 3.66(2H, q, J 7.2 Hz), 2.71 (3H, s), 1.56-1.43 (3H, m), 0.90-0.76 (9H, m).

Regioisomer (B) : White crystalline solid (9% yield): m.p. 133° C.

Analysis calculated for C₂₂ H₂₈ N₄ O₄ S.0.2H₂ O; Requires C 58.96, H6.39, N 12.50, S 7.07; Found C 59.00, H 6.31N 12.47, S 7.07.

i.r. (CHCl₃) 1730, 1335, 1150 cm⁻¹

delta_(H) 8.99 (1H, s), 8.24 (1H, d, J 5.7 Hz), 7.98 (1H, s), 7.59 (2H,d, J 8! e. 3 Hz), 7.18-7.05 (3H, m), 5.36 (2H, s), 4.52-4.43 (1H, m), 365 (2H 7 1 Hz), 2 70 (3H, s), 1 58-1 39 (3H, m), 0.88-0.76 (9H, m).

EXAMPLEs 56-63

The compounds of Examples 56-63 were prepared by the method of Example53 Steps (a) and (b) starting from the appropriate4bromomethylphenylsulphonylamino acid derivative.

56. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinei-propyl ester and (B)N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineipropyl ester ##STR78##

Regioisomer ! (A): White crystalline solid (7% yield for last step afterchromatography (silica: 6% methanol in DCM)): m.p. 133°-135° C.

Analysis caleulated for C₂₄ H₃₂ N₄ O₄ S. 0.5H₂ O; Requires C 59.85, H6.91, N 11.63; Found C 59.96, H 6.77, N 11.42.

i.r. (CHCl₃) 3020, 1740, 1340, 1190 cm⁻¹

delta_(H) 8.6_(s) (1H, s), 8.41 (1H, s), 7.75 (2H, d, J 8.3 Hz), 7.64(1H, d, J 5.0 Hz), 7.16 (2H, d, J 8.3 Hz), 5.46 (2H, s), 4.72-4.54 (2H,m), 2480 (3H, s), 2.59 (3H, s), 1.63-1.52 (3H, m), 0.99-0.91 (12H, m).

Regioisomer (B): Yellow oil (7% yield).

Analysis calculated for C₂₄ H₃₂ N₄ O₄ S.0.2H₂ O; Requires C 59.85, H6.91, N 11.63; Found C! 59.81, H 6.81, N 11.42.

i.r. (CDCl₃) 3010, 1760, 1170 cm⁻¹

delta_(H) 9.01! (1H, s), 8.35 (1H, d, J 5.3 Hz), 7.73 (2H, d, J 8.3 Hz),7.11 (3H, br d, J 7.8 Hz), 5.36 (2H, s), 4.69-4.53 (2H, m), 2.81 (3H,s), 2.57 (3H, s), 1.63-1.52 (3H, m), 1.00-0.91 (12H, m).

57. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester and (B)N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinen-butyl ester ##STR79##

Regioisomer (A): Colourless oil (6% yield for last step afterchromatography (silica: 4% methanol in DCM)):

Analysis calculated for C₂₅ H₃₄ N₄ O₄ S.0.3H₂ O; Requires C 61.03, H7.09, N 11.39; Found C 60.94, H 7.01, N 11.10.

i.r. (CHCl₃) i1730, 1340, 1145 cm⁻¹

delta_(H) 8.56 (1H, s,), 8.38 (1H, d, J 5.5 Hz), 7.68 (2H, d, J 8.3 Hz),7.57 (1H, d, J 5.4 Hz), 7.11 (2H, d, J 8.3 Hz), 5.40 (2H, s), 4.57 (1H,t, J 7.1 Hz), 3.68-3.78 (2H, m), 2.76 (3H, s), 2.54 (3H, s), 1.55 (3H,m), 1.35 (2H, m), 1.17 (2H, m), 0.88 (3H, d, J 6.1 Hz), 0.87 (3H, d, J5.9 Hz), 0.78 (3H, t, J 7.2 Hz).

Regioisomer (B): Colourless oil (9% yield):

Analysis calculated for C₂₅ H₃₄ N₄ O₄ S.0.3H₂ O; Requires C 61.03, H7.09, N 11.39, S 6.52; Found C 61.05, H 7.03, N 11.33, S 6.80.

i.r. (CHCl₃) 1730, 1335, 1145 cm⁻¹

delta_(H) 8.94 (1H, s), 8.28 (1H, d, J 5.6 Hz), 7.64 (2H, d, J 8.4 Hz),7.09-7.04 (3H, m), 5.32 (2H, s), 4.55 (1H, m), 3.76-3.65 (2H, m), 2.75(3H, s), 2.50 (3H, s), 1.53 (3H, m), 1.33 (2H, m), 1.15 (2H, m), 0.87(6H, br d, J 4.6 Hz), 0.76 (3H, t, J 7.2 Hz).

58. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester and (B)N-methyl-N-4-(1H-2methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinebenzyl ester ##STR80##

Regioisomer (A) : Colourless oil (5% yield for last step afterchromatography (silica: 5% methanol in DCM)):

i.r. (CDCl₃) 1735, 1340, 1150 cm⁻¹

delta_(H) 8.99 (1H, br s), 8.40 (1H, d, J 5.4 Hz), 7.76-7.65 (3H, m),7.30-7.21 (3H, m), 7.20-7.12 (2H, m), 7.07 (2H, br d, J 8.3 Hz), 5.57(2H, s), 4.89 (2H, s), 4.78-4.70 (1H, m), 2.78 (3H, s), 2.62 (3H, s),1.68-1.57 (3H, m), 0.98-0.89 (6H, m).

Regioisomer (B): Pale yellow oil (2% yield):

Analysis calculated for C₂₈ H₃₂ N₄ O₄ S.1.6H₂ O; Requires C 61.21, H6.46, N 10.20; Found C 61.10, H 6.06, N 10.15.

i.r. (CDCl₃ ) 1735, 1340, 1160 cm⁻¹

delta_(H) 9.06 (1H, br s), 8.38 (1H, d, J 5.0 Hz), 7.72 (2H, d, J 8.5Hz), 7.33-7 25 (3H, m), 7.20-7.10 (3H, m), 7.04 (2H, d, J 8.3 Hz), 5.36(2H, S), 4.88 (1H, d, J 12.5 Hz), 4.85 (1H, d, J 12.8 Hz), 4.80-4.70 (H,m), 2.81 (3H, s), 2.58 (3H, s), 1.70-1.58 (3H, m), 1.00-0.90 (H, m).

59. (A) N-Allyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl esterand (B)N-allyl-N-4-(1H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR81##

Regioisomer (A) : White crystalline solid (9% yield for last step afterchrogratography (s i 1 ica: 5 -7 % methanol in DCM) and crystallisationfrom ethyl acetate): m.p. 83°-84° C.

Analysis calulated for C₂₄ H₃₀ N₄ O₄ S; Requires C 61.26, H 6.43, N11.91; Found C 60.92, H 6.45, N 11.76.

i.r. (CHCl₃) t2960, 1730, 1340, 1150 cm⁻¹

delta_(H) 8.52 (1H, s), 8.29 (1H, d, J 5.5 Hz), 8.04 (1H, s), 7.59-7.54(3H, m), 7.14 (2H, d, J 8.3 Hz), 5.76-5.60 (1H, m), 5.40 (2H, s),5.03-4.9d (2H, m), 4.37 (1H, dd, J 9.3, 5.4 Hz), 3.71 (1H, dd, J 16.7,5. Hz), 3.57-3.46 (3H, m), 1.54-1.41 (3H, m), 0.77 (3H, t, J 7.1 Hz ,0.75 (3H, d, J 7.1 Hz), 0.70 (3H, d, J 6.1 Hz).

Regioisomer (B): Yellow oil (15% yield)

i.r. (CHCl₃) 2960, 1730, 1340, 1150 cm⁻¹

delta_(H) 8. (1H, s), 8.09 (1H, d, J 5.6 Hz), 7.92 (1H, s), 7.43 (2H, d,J 8 3 Hz), 7.02 (2H, d, J 8.3 Hz), 6.98 (1H, d, J 5.5 Hz), 5.67-5.51 (H,m), 5.26 (2H, s), 4.95-4.81 (2H, m), 4.37 (1H, dd, J 9.3, 5.4 [z), 3.79(1H, dd, J 16.7, 5.4 Hz), 3.65-3.55 (3H, m), 1.44-1.32 (, m), 0.66 (3H,t, J 7.0 Hz), 0.65 (3H, d, J 6.9 Hz), 0.60 (H, d, J 6.0 Hz).

delta_(C) 170 30, 144.18, 142.47, 141.63, 140.38, 139.38, 139.20, 7.83,134.75, 127.44, 126.89, 116.79, 104.95, 60.34, 57.53, 47.52, 38.2,23.46, 21.93, 20.47, 13.17.

60. (A)N-Allyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B) N-allyl-N-4-(1H-2methylimidaz[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester ##STR82##

Regioisomer (A): Yellow oil (8% yield for last step after chromatography(silica: 6% methanol in DCM))

i.r. (CHCl₃) 2960, 1730, 1340, 1160 cm⁻¹

delta_(H) 8.48 (1H, s), 8.30 (1H, d, J 5.5 Hz), 7.62 (2H, d, J 8.4 Hz),7.50 (1 d, J 5.4 Hz), 7.04 (2H, d, J 8.4 Hz), 5.79-5.63 (1H, m), 5.3(2H, s), 5.06-4.93 (2H, m), 4.41 (1H, dd, J 9.3, 5.3 Hz), 3.82 (1[, dd,J 16.7, 5.4 Hz), 3.73-3.59 (3H, m), 2.48 (3H, s), 1.57-1.42 (3H, m),0.85 (3H, t, J 7.0 Hz), 0.79 (3H, d, J 6.1 Hz), 0.75 (3H, d, J 6.2 Hz).

delta_(C) 170.56, 154.79, 147.43, 141.78, 139.64, 139.4-7, 132.59,131.97, 127.83, 126.36, 116.99, 113.57, 60.57, 57.72, 47.76, 46.63,38.47, 23.69, 22.16, 20.71, 13.55.

Regioisomer (B): White crystalline solid from ethyl acetate (12% yield):m.p. 132°-133° C.

i.r. (CHCl₃) 2960, 1730, 1340, 1150 cm⁻¹

delta_(H) 8.97 (1H, s), 8.30 (1H, d, J 5.5 Hz), 7.69 (2H, d, J 8.4 Hz),7.11-7.06 (3H, m), 5.87-5.71 (1H, m), 5.34 (2H, s), 5.14-5.01 (2H, m),4.48 (1H, dd, J 9.4, 5.3 Hz), 3.89 (1H, dd, J 16.7, 5.4 Hz), 3.81-3.67(3H, m), 2.53 (3H, s), 1.65-1.51 (3H, m), 0.95 (3H, t, J 7.2 Hz), 0.87(3H, d, J 6.1 Hz), 0.82 (3H, d, J 6.3 Hz).

delta_(C) 169.35, 151.96, 140.29, 140.03, 138.56, 138.24, 138.12,133.82, 126.53, 125.22, 115.76, 103.36, 59.35, 56.53, 46.57, 45.20,37.28, 22.51, 20.97, 19.51, 12.33.

61. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycinemethyl ester and (B) N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D, L-allylglycinemethyl ester ##STR83##

Regioisomer (A): Off-white crystalline solid (5% yield for last stepafter chromatograPhy (silica: 5% methanol in DCM)): m.p 142° C.

i.r. (CDCl₃) 1740, 1340, 1155 cm⁻¹

delta_(H) 8.61 (1H, s), 8.43 (1H, d, J 5.5 Hz), 7.76 (2H, d, J 8.5 Hz),7.63 (1H, d, J 5.4 Hz), 7.17 (2H, d, J 8.4 Hz), 5.76-5.58 (1H, m), 46(2H, s), 5.18-5.03 (2H, m), 4.66 (1H, dd, J 9.9, 5.9 Hz), 3.45 3H, s),2.80 (3H, s), 2.72-2.56 (1H, m), 2.61 (3H, s), 2.45-2.29 1H, m).

Regioisomer (B): Off-white crystalline solid (5% yield) : m.p. 138° C.

Analysis calculated for C₂₁ H₂₄ N₄ O₄ S; Requires C 58.86, H 5.65, N13.07; Found C 58.70, H 5.69, N 12.98.

i.r. (CDCl₃) 1740, 1340, 1170 cm⁻¹

delta_(H) 9.02 (1H, s), 8.37 (1H, d, J 5.6 Hz), 7.76 (.2H, d, J 8.4 Hz),7.18-7 12 (3H, m), 5.76-5.58 (1H, m), 5.39 (2H, s), 5.18-5.04 (2H, m),4.7 (1H, dd, J 9.8, 5.9 Hz), 3.46 (3H, s), 2.81 (3H, s), 2.72-2.54 (1H,m), 2.59 (3H, s), 2.46-2.30 (1H, m).

62. (A)N-][ethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycineethyl ester and (B) N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-D,L-allylglycine ethyl ester##STR84##

Regioisomer (A) : Pale yellow oil (1% yield for last step afterchromatography (silica: 5% methanol in DCM):

Analysis calclated for C₂₂ H₂₆ N₄ O₄ S. 1.3H₂ O; Requires 6.71, H 6.19,N 12.02; Found 6.80, H 5.87, N 11.66.

i.r. (CDCl₃) 1735 cm⁻¹

delta_(H) 8.76 (1H, br s), 8.45 (1H, d, J 5.3 Hz), 7.80 (2H, d, J 8.4Hz), 7.71 (1H, d, J 5.6 Hz), 7.19 (2H, d, J 8.3 Hz), 5.80-5.60 (1H, m),5.52 (2H, s), 5.20-5.05 (2H, m), 4.66 (1H, dd, J 9.8, 5.8 Hz), 3.93 (2H,q, J 7.1 Hz), 2.82 (3H, s), 2.74-2.60 (1H, m), 2.65 (3H, s), 2.50-2.32(1H, m), 1.05 (3H, t, J 6.9 Hz).

Regioisomer (B): Pale yellow oil (1% yield):

Analysis calculated for C₂₂ H₂₆ N₄ O₄ S. 0.4H₂ O; Requires C58.75, H6.01, N 12.46; Found C 58.68, H 5.99, N 12.14.

i.r.(CDCl₃) 1730 cm⁻¹

delta_(H) 9.04 (1H, s), 8.38 (1H, d, J 5.6 Hz), 7.78 (2H, d, J 8.5 Hz),7.20-7.12 (3H, m), 5.80-5.60 (1H, m), 5.41 (2H, s), 5.20-5.04 (2H, m),4.67 (1H, dd, J 10.0, 5.8 Hz), 3.90 (2H, q, J 7.1 Hz), 2.82 (3H, s).,2.76-2.60 (1H, m), 2.61 (3H, s), 2.47-2.30 (1H, m), 1.04 (3H, t, J 7.3Hz).

63. (A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-isoleucineallyl ester and (B)N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-isoleucineallyl ester ##STR85##

Regioisomer (A): Yellow oil (3% yield for last step after chromatography(silica: 5-7% methanol in DCM)):

i.r. (CDCI₃) 2950, 2220, 1735, 1610, 1400, 1340, 1150 cm⁻¹

delta_(H) 8.53 (1H, s), 8.36 (1H, d, J 5.5 Hz), 7.66 (2H, d, J 7.9 Hz),7.56 (1H, d, J 5.5 Hz), 7.08 (2H, d, J 8.1 Hz), 5.61-5.45 (1H, m), 5,39(2H, s), 5.07-4.98 (2H, m), 4.24-3.97 (3H, m), 2.78 (3H, s), 2.54 (3H,s), 1.92-1.72 (1H, m), 1.58-1.49 (1H, m), 1.16-0.95 (1H, m), 0.89-0.72(6H, m).

delta_(C) 169.44, 154.88, 147.68, 142.24, 139.73, 138.83, 132.82,132.10, 130.93, 128.03, 126.52, 118.63, 113.94, 64.91, 63.13, 46.85,33.50, 29.98, 24.75, 15.08, 13.80, 10.17.

Regioisomer (B): Yellow oil (3% yield):

i.r. (CDCl₃) 2950, 2220, 1735, 1610, 1340, 1150 cm⁻¹

delta_(H) 8.83 (1H, s), 8.17 (1H, d, J 5.0 Hz), 7.51 (2H, d, J 8.3 Hz),7.00-6.93 (3H, m), 5.50-5.31 (1H, m), 5.24 (2H, s), 4.97-4.88 (2H, m),4.12-4.02 (2H, m), 3.96-3.86 (1H, m), 2.68 (3H, s), 2.41 (3H, s),1.82-1.62 (1H, m), 1.48-1.30 (1H, m), 1.06-0.86 (1H, m), 0.75-0.69 (6H,m).

delta_(C) 169.18, 153.10, 141.58, 141.34, 139.74, 139.64, 139.39,138.32, 130.65, 127.65, 126.31, 118.47, 104.43, 64.64, 62.86, 46.35,33.24, 29.76, 24.51, 14.82, 13.52, 9.88.

EXAMPLE 64

(A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemorpholinoamide and (B)N-methyl-N-4-(1H-2-methylimdazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemorpholinoamide ##STR86##

(A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucinemorpholinoamide and (B) N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine morpholinoamide wereprepared by the method of Example 25 Step (a), Example 11 Step (b),Example 5 Step (a) and Example 35 Step (b) starting fromN-benzyloxycarbonyl-L-leucine p-nitrophenyl ester and morpholine.

Regioisomer (A): Pale yellow oil (3% yield for last step afterchromatography (silica: 5% methanol in DCM)).

i.r. (CDCl₃) 1635, 1340, 1150 cm⁻¹

delta_(H) 8.68 (1H, br s), 8.43 (1H, br s), 7.73 (2H, d, J 8.3 Hz), 7.66(1H, d,! J 5.2 Hz), 7.19 (2H, d, J 8.4 Hz), 5.49 (2H, s), 4.85 (1H, t, J7.4 Hz), 3.80-3.34 (8H, m), 2.85 (3H, s), 2.61 (3H, s), 1.70-1.57 (1H,m), 1.50-1.33 (1H, m), 1.15-0.99 (1H, m), 0.84 (3H, d, J 6.3 Hz), 0.83(3H, d, J 6.5 Hz).

Regioisomer (B) : Pale yellow oil (3% yield).

i.r. (CDCl₃) 1640, 1340, 1155 cm⁻¹

delta_(H) 9.02 (1H, s), 8.35 (1H, d, J 5.5 Hz), 7.69 (2H, d, J 8.3 Hz),7.16-7.08 (3H, m), 5.39 (2H, s), 4.83 (1H, t, J 7.3 Hz), 3.80-3.34 (SH,m), 2.85 (3H, s), 2.57 (3H, s), 1.68-1.56 (1H, m), 1.48-1.34 (1H, m),1.10-0.92 (1H, m), 0.83 (3H, d, J 6.6 Hz), 0.82 (3H, d, J 6.7 Hz).

EXAMPLE 65N-Propyl-N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR87##

N-Allyl-N-4 -(3H-imidazo[4, 5 -c]pyridylmethyl)phonylsulphonyl-L-leucineethyl ester (100 mg, 0.21 mmol) was dissolved in ethanol (15 ml) andadded to a suspension of 10% palladium on carbon (100 mg) in ethylacetate (10 ml) under argon. The flask was evacuated and a ballon ofhydrogen was attached. The mixture was stirred at room temperature for 3h, the catalyst filtered off and the solution concentrated under reducedpressure to give a yellow oil. Purification by chromatography (silica:4% methanol in DCM) gave N-propyl -N-4-(3H-imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester(7 mg, 7%) as a colourless oil.

i.r. (CHCl₃) 2960, 1730, 1340, 1145 cm⁻¹

delta_(H) 8.71 (1H, s), 8.49 (1H, d, J 5.3 Hz), 8.09 (1H, s), 7.84 (2H,d, J 8,3 Hz), 7.76 (1H, d, J 5.7. Hz), 7.31 (2H, d, J 8.3 Hz), 5.52 (2H,s), 4.52 (1H, dd, J 9.4, 5.2 Hz), 3.81 (2H, q, J 7.1 Hz), 3.24-2,96 (2H,m), 1.82-1.46 (5H, m), 0.97 (3H, t, J 7.3 Hz), 0.95 (3H, d, J 5.7 Hz),0.93 (3H, d, J 6.3 Hz), 0.84 (3H, t, J 7.3 Hz).

delta_(C) 171.07, 149.06, 145.68, 142.40, 140.48, 139.10, 133.42,128.43, 122.33, 115.29, 60.99, 58.29, 48.77, 47.83, 39.40, 24.40, 22.78,21.42, 13.85, 11.38.

EXAMPLEs 66 and 67

The compounds of Examples 66 and 67 were prepared by the method ofExample 65 starting from the regioisomers (A) and (B) of Example 60respectively.

66.N-Propyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR88##

Off white Crystalline solid (80% yield): m.p. 90°-91° C.

i.r. (CHCl₃) 2960, 1730, 1340, 1145 cm⁻¹

delta_(H) 8.57 (IN, s), 8.39 (1H, d, J 5.4 Hz), 7.73 (2H, d, J 8.3 Hz),7.59 (1H, d, J 4.4 Hz), 7.12 (2H, d, J 8.3 Hz), 5.41 (2H, s), 4.48-4.42(! H, m), 3.76 (2H, q, J 7.1 Hz), 3.18-2.91 (2H, m), 2.57 (3H, s),1.76-1.41 (SH, m), 0.93 (3H, t, J 7.1 Hz), 0.87 (6H, br d, J 4.9 Hz),0.79 (3H, t J 7.4 Hz).

delta_(C) 170.96, 155.00, 147.81, 142.26, 140.10, 139.54, 132.91,132.16, 128.26, 114.02, 60.87, 58.15, 47.69, 47.00, 39.30, 24.30, 22.68,21.33, 13.88, 13.76, 11.28.

67.N-Propyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR89##

Off white crystalline solid (75% yield): m.p. 107°-108° C.

i.r. (CHCl₃) 2960, 1730, 1340, 1140 cm⁻¹

delta_(H) 8.96 (1H, s), 8.30 (1H, d, J 5.6 Hz), 7.69 (2H, d, J 8.4 Hz),7.10-7.06 (3H, m), 5.34 (2H, s), 4.46-4.40 (1H, m), 3.74 (2H, q, J 7.0Hz), 3.15-2.91 (2H, m), 2.53 (3H, s), 1.73-1.40 (SH, m), 0.93 (3H, t, J7.2 Hz), 0.88 (3H, d, J 6.0 Hz), 0.86 (3H, d, J 6.1 Hz), 0.78 (3H, t, J7.4 Hz).

delta_(C) 170.88, 153.27, 141.83, 141.71, 140.02, 139.88, 139.54,128.09, 126.44, 104.60, 60.75, 58.04, 47.61, 46.69, 39.22, 24.23, 22.60,21.25, 13.76, 13.71, 11.20.

EXAMPLE 68

(A)N-Methyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentaneand (B)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentane##STR90##

(A)N-Methyil-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentanean8 (B)N-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-2-keto-3-amino-4-methylpentanewere prepared by the method of Example 1 Step (b) followed by Example 53steps (a) and (b) starting from 2-keto-3-amino-4-methylpentanehydrochloride.

Regioisomers (A) and (B) were separated by column chromatography(silica: 5% methanol in DCM).

Regioisomer (B) : Colourless oil (4% yield for last step afterchromatography):

i.r. (CDCl₃) 1715, 1340, 1160 cm⁻¹

delta_(H) 8.94 (1H, s), 8.26 (1H, d, J 5.5 Hz), 7.66 (2H, d, J 8.3 Hz),7.13-7i00 (3H, m), 5.33 (2H, s), 4.04 (1H, d, J 10.4 Hz), 2.65 (3H, s),2.49 (3H, s), 2.07 (3H, s), 2.10-1.92 (1H, m), 0.76 (3H, d, J 6.6 Hz),0.53 (3H, d, J 6.8 Hz).

delta_(C) 205.06, 153.20, 141.87, 141.70, 139.98, 139.86, 139.59,127.74, 126.70, 104..54, 68.30, 46.60, 29.89, 29.48, 25.9q, 19.20,19.08.

EXAMPLE 69

(A) N-t-Butoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester and (B)N-t-butoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR91##

(a) N-t-Butoxycarbonylmethyl-N-4-bromomethylphenylsulphonyl-L-leucineethyl ester

N-4-Bromomethylphenylsulphonyl-L-leucine ethyl ester (1.0 g, 2.6 mmol)was dissolved in THF (50 ml) and the stirred resulting solution cooledto 0° C. and treated with potassium his (trimethylsilyl) amide (0.5 M inTHF, 5 ml). The reaction mixture was stirred for 15 min, treated witht-butyl bromoacetate (0.75 ml, 0i.51 mmol) and allowed to warm to roomtemperature overnight. The reaction mixture was then diluted with ethylacetate and iwashed with brine. The organic layer was dried overanhydrous magnesium sulphate, filtered and concentrated under reducedpresisure. Purification of the residue by chromatography (silica: 15%ethyl acetate in hexane) gaveN-t-butoxycarbonylmethyl-N-4-bromomethylphenylsulphonyl-L-leucine ethylester (0.8 g, 54%) as a colourless oil.

delta_(H) 7.89 (2H, d, J 8.2 Hz), 7.50 (2H, d, J 8.3 Hz), 4.60 (2H, s),4.39-4.30 (1H, m), 4.11 (1H, d, J 18.5 Hz), 3.96 (1H, d, J 18.5 Hz),3.90 (2H, q, J 7.1 Hz), 1.90-1.73 (1H, m), 1.60-1.39 (2H, m), 1.47 (9H,s) 1.08 (3H, t, J 7.0 Hz), 0.88 (3H, d, J 6.7 Hz), 0.83 (3H, d, J 6.5Hz).

(b) (A) N-t-!Butoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-tbutoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethylphenylsulphonyl-L-leucineethyl ester

(A) N-t-B,carbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-t-butoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethylphenylsulphonyl-L-leucineethyl ester were prepared by the procedure described in Example 35 Step(b) utilisingN-t-butoxycarbonylmethyl-N-4-bromomethylphenylsulphonyl-L-leucine ethylester.

Regioisome (A): Yellow oil (6% yield after chromatography (silica: 7methanol in DCM)):

Analysis calculated for C₂₈ H₃₈ N₄ O₆ S.0.8H₂ O; Requires 58.68, H 6.96,N 9.78; Found C 58.76, H 6.72, N 9.73.

i.r. (CHCl₃ 2215, 1740 cm⁻¹

delta_(H) 8.5 (1H, s) 8.33 (1H, d, J 5.5 Hz), 7.78 (2H, d, J 8.3 Hz),7.53 (.H, d, J 5.6 Hz), 7.09 (2H, d, J 8.2 Hz), 5.38 (2H, s), 4.18 (1H,J 8.0 Hz), 4.01 (1H, d, J 22.0 Hz), 3.85 (1H, d, J 22.0 Hz), .82-3.68(2H, m), 2.52 (3H, s), 1.72-1.61 (1H, m), 1.45-1.28 H, m), 1.35 (9H, s),0.92 (3H, t, J 7.1 Hz), 0.74 (3H, d, J 6.6 Hz), 0.68 (3H, d, J 6.5 Hz).

Regioisomer (B): Yellow oil (5% yield):

Analysis calculated for C₂₈ H₃₈ N₄₀₆ S.0.9H₂ O; Requires C 8.50, H 6.98,N 9.75; Found C 8.45, H 6.68, N 9.74.

i.r. (CHCl₃) 2210, 1735 cm⁻¹

delta_(H) 8.95 (1H, s), 8.28 (1H, d, J 5.6 Hz), 7.79 (2H, d, J 8.3 Hz),7.08 (3 d, J 7.9 Hz), 5.33 (2H, s), 4.20 (1H, t, 8.2 Hz), 4.03 (1H, d, J22.0 Hz), 3.87 (1H, d, 22.0 Hz) 3.83-3.71 (2H, m), 2.51 (3H, s)1.73-1.62 (1H, m), 1.51-1.32 (2H, m), 1.37 (9H, s), 0.95 (3H, t, J 7.1Hz), 0.76 (3H, d, J 6.6 Hz), 0.70 (3H, d, J 6.5 Hz).

EXAMPLE 70

(A)N-Ethoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]-pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-ethoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR92##

(a) N-Ethoxycarbonylmethyl-N-4-bromomethylphenylsulphonyl-L-leucineethyl ester

N-4-Bromomethylphenylsulphonyl-L-leucine ethyl ester (2.0 g, 5.1 mmol)was dissolved in dry THF (50 ml) and the stirred solution was treated=with potassium hydride (35% dispersion in oil, 0.583 g). After 20 min.ethyl bromoacetate (1.70 g, 10.2 mmol) was added and the resultingmixture allowed to stir overnight. Ethyl acetate and brine were added,and the organic layer was separated dried over anhydrous magnesiumsulphate, filtered and concentrated under reduced pressure. Purificationof the residue by chromatography (silica: 1:3 ethyl acetate/hexane) gaveN-ethoxycarbonylmethyl-N-4 -bromomethylphenylsulphonyl-L-leucine ethylester (1.89 g, 77%) as a colourless oil.

delta_(H) 7.91 (2H, d, J 8.3 Hz), 7.52 (2H, d, J 8.2 Hz), 4.61, 4.49(2H, 2s), 4.38, (1H. br t, J 7.2 Hz), 4.28-4.03 (4H, m), 3.92 (2H, q, J7.1 Hz), 1.90-1.70 (1H, m), 1.60-1.48 (2H, m), 1.40-1.22 (3H, m), 1.10(3H, t, J 7.0 Hz), 0.88 (3H, d, J 6.6 Hz), 0.84 (3H, d, J 6,6 Hz).

(b) (A)N-Ethoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-ethoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester

(A)N-Ethoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-ethoxycarbonylmethyl-N-4-(1H-2-met;hylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester were prepared by the procedure described in Example 35 Step(b) utilisingN-ethoxycarbonylmethyl-N-4-bromomethylphenylsulphonyl-L-leucine ethylester.

Regioisomer (A): Yellow oil (4%. yield after chromatography (silica: 5%methanol in DCM)):

Analysis calculated for C₂₆ H₃₄ N₄ O₆ S.0.5H₂ O; Requires C 57.86, H6.35, N 10.39; Found C 58.01, H 6.38, N 10.19.

i.r. (CHCl₃) 3690, 2960, 1735, 1600, 1390, 1155 cm⁻¹

delta_(H) 8.58 (1H, s), 8.41 (1H, d, J 5.5 Hz), 7.88 (2H, d, j 8.3 Hz),7.61 (1H, J 5.3 Hz), 7.16 (2H, d, J 8.3 Hz), 5.44 (2H, s), 4.30-3.78(7H, m), 2.58 (3H, s), 1.73-1.65 (1H, m), 1.54-1.44 (2H, m) 1.23 (3R,dt, J 7.1 Hz), 1.01 (3H, =, J 7.1 Hzi, 0.80 (3H, d, J 6.6 Hz), 0.74 (3H,d, 6.5 Hz).

Regioisomer (B): Yellow oil (4% yield):

Analysis calculated for C₂₆ H₃₄ N₄ O₆ S.0.SH₂ O; Requires C 57,86, H6.35, N 10.39; Found C 58.05, H 6.39, N 10.35.

i.r. (CHCl₃) 3680, 2960, 1735, 1610, 1585, 1340, 12:80, 1155 cm⁻¹

delta_(H) 8.98 (1H, s), 8.31 (1H, d, J 5.4 Hz), 7.83 (2H, d, J 8.4 Hz),=.7.13-7.09 (3H, m), 5.36 (2H,. s), 4.27-3.78 (7R, m), 2.55 (3H, s),1.71-1.66 (1H, m), 1.50-1.43 (2H, m), 1.21 (3H, dt, J 7.0, 1.5 Hz), 0.99(3H, d=, J 7.1, 1.8 Ha), Q.79 (3H, d, J 6.5 Hz), 0.72 (3H, J 6,5 Hz).

EXAMPLE 71

(A) N-Methoxycarbonylmethyl-N-4-(3H-2 -methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester and (B)N-methoxycarbonylmethyl-N-4-(1H-2-methyl imidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester ##STR93##

(A) N-Methoxycarbonylmethyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine e.thyl ester and (B)N-methoxycarbonylmethyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester were prepared by the procedure described in Example 70starting from methyl bromoacetate.

Regioisomer (A): Colourless oil (3% yield after chromatography (silica:5% methanol in DCM):

i.r. (CHCl₃) 2960, 2220, 1735, 1610, 1345, 1155 cm⁻¹

delta_(H) 8.56 (1H, S), 8.39 (1H, d, J 5.7 Hz), 7.84 (2H, d, J 8.4 Hz),7.59 (1H, d, J 5.5 Hz), 7.15 (2H, d, J 8.2 Hz), 5.43 (2H, s), 4.25 (1H,d, J 8.2, 6.6 Hz), 4.18 (1H, d, J 18.9 Hz), 4.03 (1H, d, J 18.4 Hz),3.89-3.78 (2H, m), 3.66 (3H, s), 2.57 (3H, s), 1.70-1.65 (1H, m),1.49-1.42 (2H, m), 0.98 (3H, t, J 7.2 Hz), 0.79 (3H, d, J 6./6 Hz), 0.72(3H, d, 6.4 Hz).

delta_(C) 169.i45, 168.52, 153.80, 146.40, 141.03, 138.89, 138.00,131.61, 130.85, 127.46, 125.46, 125.26, 112.69, 59.79, 56.06, 50.84, 456., 44 80, 43 93, 37 95, 22 70, 21.08, 20.04, 12.52, 12.43.

Regioisomer (B): Yellow oil (2% yield):

i.r. (CHCl₃) 2960, 2220, 1735, 1610, 1340, 1155 cm⁻¹

delta_(H) 9.03 (1H, s), 8.36 (1H, d, J 5.5 Hz), 7.88 (2H, d, J 8.5 Hz),7.17-7.11 (3H, m), 5.39 (2H, s), 4.28 (1H, dd, J 8.2, 6.5 Hz), 4.22 (1H,d, J 18.3 Hz), 4.06 (1H, d, J 18.5 Hz), 3.93-3.77 (2H, m), 3.i70 (3H,s), 2.58 (3H, s), 1.76-1.64 (1H, m), 1.53-1.45 (2H, m), 1.03 (3H, t, J7.1 Hz), 0.82 (3H, d, J 6.6 Hz), 0.76 (3H, d, J 6.5 Hz).

delta_(c) 169.60, 168.61, 151.82, 140.74, 140.69, 138.80, 138.03,127.50, 126180, 125.22, 103.25, 59.79, 56.07, 50.85, 45.46, 43.92,37.99, 22.73, 21.10, 20.09, 12.49.

EXAMPLE 72

(A) N-Methyl-N-3-chloro-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-methyl-N-3-chloro-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR94##

(a) 3-Chloro-4-bromomethylphenylsulphonyl chloride

N-Bromosuccinimide (13.76 g, 76 mmol) was added to a stirred solution of3-chloro-4-toluenesulphonyl chloride (12 g, 76 mmol) in CCl₄ (120 ml)under argon. After one hour benzoyl peroxide (0.92 g, 3.8i mmol) wasadded and the reaction mixture refluxed overnight. The mixture wasallowed to cool, the resulting white precipitate filtered off and thefiltrate evaporated to a yellow oil. PurifiCation of the residue bychromatography over silica gel (3% ethyi acetate in hexane) afforded3-chloro-4-bromomethylphenylsulphonyl chloride (3.3 g, 14%) as acolourless oil.

delta_(H) 8.30-7.05 (3H, m), 4.62 (2H, s).

(b) N-3-Chloro-4-bromomethylphenylsulphonyl-L-leucine ethyl ester

N-3-Chloro-4-bromomethylphenylsulphonyl-L-leucine ethyl ester wasprepared following the procedure of Example 35 Step (a) utilising3-chloro-4-bromomethylphenylsulphonyl chloride in lieu of4-bromomethylphenylsulphonyl chloride.

Colourless oil (20% yield after purification by chromatography oversilica gel (cluett 1:6 ethyl acetate/hexane):

delta_(H) 7.8+(1H, d, J 3.0 Hz), 7.77-7.72 (1H, m), 7.62 (1H, d, J 8.2Hz), 5140 (1H, d, J 9.4 Hz), 4.71 (2H, s), 4.04-3.84 (3H, m), 1.90-1.71(! IH, m), 1.60-1.46 (2H, m), 1.17-1.09 (3H, m), 0.93 (6H, m).

(c) N-Methyl-N-3-chloro-4-bromomethylphenylsulphonyl-L-leucine ethylester

N-Methyl-N-13-chloro-4-bromomethylphenylsulphonyl-L-leucine ethyl esterwas prepared following the procedure of Example 53 Step (a), utilisingN-3-chloro-4-bromomethylphenylsulphonyl-L-leucine ethyl ester in lieu ofN-4-bromomethylphenyl-L-leucine ethyl ester, as an oil which was useddirectly in the next step.

(d) (A) N-Methyl-N-3-chloro-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester and (B)N-methyl-N-3-chloro-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl ester

(A) N-Methyl-N-3-chloro-4 -(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine ethyl esterand (B)N-methyl-N-3-chloro-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester were prepared by the method of Example 53 Step (b)uti[lising N-methyl-3-chloro-4-bromomethylphenylsulphonyl-L-leucineethyl ester in lieu of N-methyl-4-bromomethylphenylsulphonyl-L-leucineethyl ester and 3:1 THF/DMF as solvent.

Regioisomer (A): Colourless oil (2% yield after chromatography (silica:6% methanol in DCM)):

i.r. (CHCl₃) 2960, 1730, 1610, 1335 cm⁻¹

delta_(H) 8.54 (1H, s), 8.43 (1H, d, J 5.5 Hz), 7.88 (1H, d, J 1.5 Hz),7.63 (1H, d, J 5.5 Hz), 7.52 (1H, dd, J 8.2, 1.4 Hz), 6.58 (1H, d, J 8.2Hz), 5.49 (2H, s), 4.61 (1H, m), 3.87 (2H, q, J 7.1 Hz), 2.79 (3H, s),2.57 (3H, s), 1.61-1.59 (3H, m), 1.03 (3H, t, J 7.1 Hz), 0.98-0.91 (6H,m).

delta_(C) 170. I13, 155117, 147.87, 142.51, 140.62, 137.01, 132.94,132.12, 128.74, 127.11, 126.32, 114.17, 61.03, 57.31, 45.10, 37.93,29.8, 24.31, 22.97, 20.93, 13.86, 13.74.

Regioisomer (B): Colourless oil (5% yield):

i.r. (CHCl₃) 2940, 1730, 1610, 1350 cm⁻¹

delta_(H) 8.97 (1H, s), 8.28 (1H, d, J 5.6 Hz), 7.81 (1H, d, J 1.8 Hz),7.46 (1H, dd, J 8.2, 1.8 Hz), 7.04 (1H, dd, J 5.4, 0.8 Hz), 6.50 (1H, d,J 8.2 Hz), 5.39 (2H, s), 4.56 (1H, m), 3.82 (2H, q, J 7.1 Hz), 2.7 (3H,s), 2.51 (3H, s), 1.55 (3H, m), 1.00 (3H, d, J 7.2 Hz), 0.9 (3H, d, J6.1 Hz), 0.89 (3H, d, J 6.1 Hz).

delta_(C) 170.50, 153.28, 142.08, 141.90, 140.36, 139.67, 139.59,136.95, 132.84, 128.52, 127.02, 126.11, 104.50, 60.67, 57.18, 44.75,37.84, 29.70, 24.22, 22.87, 20.81, 13.78, 13.63.

EXAMPLES 73-74

The compounds of Examples 73-74 were prepared by the method of Example53 Steps (c)-(h) employing the appropriate carboxylic anhydride in lieuof acetic anhydride in the final step.

73.N-Methyl-N-4-(1H-2-ethylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-n-leucineethyl ester ##STR95##

Off white crystalline solid (45% yield for last step afterchromatography (silica: 4% methanol in DCM)): m.p. 107°-108° C.

i.r. (CDCl₃ i 2960, 1730, 1340, 1150 cm⁻¹

[α]_(D) ²⁵ -14.2 (c 1.5, EtOH)

delta_(H) 9.09, (1H, s), 8.38 (1H, d, J 5.6 Hz), 7.77 (2H, d, J 8.5 Hz),7.14 (3H, m), 5.41 (2H, s), 4.64 (1H, m), 3.84 (2H, q, J 7.2 Hz), 2.86(2H, q, J 7.4 Hz), 2.83 (3H, S), 1.61 (3H, m), 1.46 (3H, t, J 7.4 Hz)! ,1.02 (3H, t, J 7.2 Hz), 0.96 (3H, d, J 6.0 Hz), 0.95 (3H, d, J 6.2 Hz).

delta_(C) 170.70, 157.67, 141 98, 140.11, 139.76, 139.14, 128.06,126.43, 104.61, 60.73, 57.06, 46.41, 37.96, 29.70, 24.28, 22.91, 20.94,20.78, 11.12.

4.N-Methyl-N-4-(1H-2-n-pentylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR96##

Yellow oil (12% yield for last step after chromatography (silica: 12%methanol in DCM)):

i.r. (CDCl₃) 2960, 1730, 1340, 1145 cm⁻¹

delta_(H) 9.07 (1H, s), 8.39 (1H, d, J 5.1 Hz), 7.76 (2H, d, J 8.7 Hz),7.11 (3H, m), 5.41 (2H, s), 4.63 (1H, m), 3.84 (2H, q, J 7.1 Hz), 2.83(1H, t, J 7.7 Hz), 2.82 (3H, s), 2.35 (1H, t, J 7.5 Hz), 1.86 (1H, m! ),1.64 (2H, m), 1.33 (6H, m), 1.02 (3H, t, J 7,2 Hz), 0.95 (9H, m).

delta_(C) 170.85, 157.39, 141.35, 140.36, 139.61, 139.39, 128.28 126.43,104.95, 60.87, 57.16, 46.64, 38.06, 31.45, 29.76, 24.38, 23.02, 22.91,22.31, 22.25, 21.03, 13.84.

EXAMPLE 75N-Acetyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-n-leucineethyl ester ##STR97##

A 1M THF solution of sodium his (trimethysilyl) amid, (1.6 ml, 1.6 mmol)was added to a stirred solution ofN-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester (0.70 g, 1.6 mmol) in dry THF (60 ml) under argon. Thesolution was cooled to 0° C. and acetyl chloride (0.11 ml) added. Themixture was allowed to warm up to room temperature and was stirredovernight. The solvent was removed under reduced pressure and theresidue purified by chromatograPhy (silica: 5% methanol in DCM) to giveN-acetyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester (0.36 g. 48%) as a colourless oil.

i.r. (CDCl₃) 2210, 1735, 1710, 1350, 1165 cm⁻¹

delta_(H) 8.57 (1H, s), 8.41 (1H, d, J 5.5 Hz), 8.03 (2H, d, J 8.5 Hz),7.61 (1H, d, J 5.4 Hz), 7.21 (2H, d, J 8.3 Hz), 5.47 (2H, s), 4.95-4.90(1H, m), 4.07 (2H, q, J 7.1 Hz), 2.58 (3H, s), 2.17 (3H, s), 2.18-2.04(1H, m), 1.82-1.63 (2H, m), 1.11 (3H, t, J 7.2 Hz), 0.96 (3H, d, J 6.5Hz), 0.92 (3H, d, J 6.5 Hz).

delta_(C) 169.57, 169.16, 154.85, 147.63, 142.18, 141.28, 139.31,132.68, 131.97, 128.93, 126.68, 113.91, 61.39, 58.67, 46.70, 39.22,25.04, 24.79, 22.66, 21.82, 13.69.

EXAMPLE 76

(A)N-Ethoxycarbonyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-ethoxycarbonyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester ##STR98##

(a) N-Ethoxycarbonyl-N-4-bromomethylphenylsulphonyl-L-leucine ethylester

A solution of sodium bis(trimethylsilyl)amide (1M in THF, 39 ml, 39mmol) was added to a stirred solution ofN-4-bromomethylphenylsulphonyl-L-leucine ethyl ester (15.0 g, 38.2 mmol)in dry THF (150 ml) at room temperature under argon. The reactionmixture was cooled to 0° C. and ethyl chloroformate (3.7 ml, 38.3 mmol)was added. The mixture was allowed to warm to room temperature and wasstirred overnight. The solvent was removed under reduce_(d) pressure andthe residue taken up in ethyl acetate (150 ml) and aqueous ammoniumchloride (100 ml) added. The organic layer was separated, washed withbrine (100 ml), dried over anhydroUs sodium sulphate, filtered andconcentrated under reduced pressure. The residue was purified bychromatography (silica: 15% ethyl acetate in hexane) to giveN-ethoxycarbonyl-N-4-bromomethylphenylsulphonyl-L-leucine ethyl ester(6.1 g, 34%) as a colourless oil.

delta_(H) 8.06 (2H, d, J 8.4 Hz), 7.55 (2H, d, J 8.4 Hz), 5.14 (1H, dd,J 8.6, 5.6 Hz), 4.63 (3H, s), 4.22-4.03 (4H, m), 2.07-1.97 (2H, m), 1.78(1H, m), 1.20 (3H, t, J 7.1 Hz), 1.10 (3H, t, J 7.2 Hz), 1.05 (3H, d, J6.4 Hz), 1.00 (3H, d, J 6.4 Hz).

(b) (A)N-Ethoxycarbonyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-ethoxycarbonyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester

(A)N-Ethoxycarbonyl-N-4-(3H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester and (B)N-ethoxycarbonyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester were prepared by the procedure described in Example 35 Step(b) utilising N-ethoxycarbonyl-N-4-bromomethylphenylsulphonyl-L-leucineethyl ester in lieu of N-4-bromomethylphenylsulphonyl-L-leucine ethylester.

Regioisomer (A): White foam (2% yield for last step after chromatography(silica: 5% methanol in DCM):

i.r. (CDCl_(3l) ) 2220, 1730, 1600, 1235, 1155 cm⁻¹

delta_(H) 8.55 (1H, s), 8.35 (1H, d, J 5.6 Hz), 7.94 (2H, d, J 8.5 Hz),7.57 (1H, d, J 6.2 Hz), 7.13 (2H, d, J 89.4 Hz), 5.42 (2H, s) 5.03 (1H,dd, J 8.6, 5.7 Hz), 4.11-3.91 (4H, m), 2.54 (3H, s), 1.91 (2H, m), 1.67(1H, m), 1.05 (3H, t, J 7.1 Hz), 0.99 (3H, t, J 7.1 Hz), 0.94 (3H, d, J6.4 Hz), 0.89 (3H, d, J 6.6 Hz).

Regioisomer (B): White foam (2% yield):

i.r. (CDCl₃) 2220, 1730, 1245, 1170 cm⁻¹

delta_(H) 8.91 (1H, s), 8.24 (1H, d, J 5.1 Hz), 7.90 (2H, d, J 8.4 Hz),7.10-7.03 (3H, m), 5.33 (2H, s), 5.01 (1H, dd, J 8.6, 5.7 Hz), 4.09-3.87(4H, m), 2.48 (3H, s) 1.89 (2H, m), 1.64 (1H, m), 1.04 (3H, t, J 7.1Hz), 0.97 (3H, t, J 7.1 Hz), 0.92 (3H, d, J 6.5 Hz), 0.87 (3H, d, J 6.6Hz).

delta_(C) 169.72, 153.25, 151.00, 141.65, 141.48, 140.77, 139.98,138.92, 12-9.69, 128.96, 125.96, 104.55, 63.32, 61.47, 58.02, 46.55,39.04, 24.66, 22.97, 21.34, 13.73, 13.68, 13.57.

EXAMPLE 77N-Methyl-N,4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineoctadecyl ester ##STR99## (a)N-Methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine

Aqueous 2M potassium hydroxide solution (2.5 ml, 5 mmol) was added to astirred solution ofN-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineethyl ester (500 mg, 1.1 mmol) in ethanol (2 ml). The reaction mixturewas stirred overnight ati room temperature. The mixture was washed withDCM, acidified to pH 5.2 and extracted with DCM. The organic extractswere evaporated to give a colourless oil. Crystallisation from methanolgaveN-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine(191 mg, 40%) as a white crystalline solid.

i.r. (KBr) 3660-3150, 1720-1695, 1610, 1325, 1145 cm⁻¹

delta_(H) (CD3OD) 8.36 (1H, s), 8.29 (1H, d, J 5.7 Hz), 7.77 (2H, d, J8.4 Hz), 7.56 (1H, d, J 5.7 Hz), 7.27 (2H, d, J 8.3 Hz), 5.61 (2H, s),4.55-4.49 (1H, m), 2.79 (3H, s), 2.59 (3H, s), 1.64-1.46 (3H, m), 0.89(3H, d, J 6.0 Hz), 0.88 (3H, d, J 5.8 Hz).

(b) N-Methyl-N-4-(1H-2-methylimidazo(4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine octadecyl ester

1-(3-Dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (139 mg,0.7 mmol), pentafluorophenol (205 mg, 1.1 mmol) and Nmethylmorpholine(80 μl, 0.7 mmol) were added to a stirred solution ofN-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucine(240 mg, 0.6 mmol) in dry DMF (5 ml) at 0° C. The mixture was stirredfor 1.5 h at 0° C. Octadecanol (300 mg, 1.1 mmol) was added and themixture allowed to warm up to ambient temperature and was stirred for 60h. Diethyl ether was added and the resultant mixture washed with water(×2), dried over anhydrous sodium sulphate, filtered and the solventremoved under reduced pressure to give a brown solid. Chromatogarphy(silica: 5 % methanol in DCM) gaveN-methyl-N-4-(1H-2-methylimidazo[4,5-c]pyridylmethyl)phenylsulphonyl-L-leucineoctadecyl ester (125 mg, 33%) as a brown oil.

i.r. (CDCl₃) 2930, 1735, 1340, 1150 cm⁻¹

delta_(H) 9.00 (1H, br s), 8.33 (1H, br s), 7.70 (2H, d, J 8.3 Hz), 7.10(3H, m), 5.36 (2H, s), 4.63-4.57 (1H, m), 3.83-3.66 (2H, m), 2.79 (3H,s), 2.55 (3H, s), 1.58-1.55 (3H, m), 1.41-1.31 (2H, m), 1.30-1.22 (30H,m), 0.92-0.82 (9H, m).

delta_(C) 170.89, 153.30, 141.96, 141.86, 140.14, 139.61, 139.24,128.12, 126.55, 104.62, 65.02, 57.12, 46.79, 38.11, 31.80, 29.73, 29.57,29.45, 29.36, 29.23, 29.04, 28.23, 25.70, 24.35, 22.92, 2.56, 21.00,13.99.

COMPARATIVE EXAMPLE N-Cyclohexyl-N-methyl-4-(1H-imidazo[4,5-c]pyridylmethyl)benzamide

This compound is not within the scope of the invention: It has beenincluded here as a comparative example. This compound was described inEP-A-0260613. ##STR100##

To an ice cold stirred solution of N-methylcylohexylamine (20 ml, 0.15mol) and triethylamine (22 ml) in dry THF (100 ml) under argon wasslowly added p-toluoyl chloride (20 ml, 0.15 mol). A white precipitateformed. The ice bath-was removed and. the mixture stirred at ambienttemperature for 24 h. Ice cold 2M hydrochloric acid (100 ml) was addedand the organic layer separated. The aqueous layer was extracted withethyl acetate (3×100 ml). The combined organics were washed with brine(3×100 ml), dried over anhydrous sodium sulphate, filtered andevaporated to give the crude amide, which was crystallised from hexaneto give N-cyclohexyl-N-methyl-4-methylbenzamide (30.9 g, 87%) as a whitecrystalline solid.

m.p. 70°-71° C.

i.r. (nujol) 2920, 1640 cm⁻¹

delta_(H) 7.26 (2H, d, J 8.0 Hz), 7.18 (2H, d, J 8.3 Hz), 4.50, 3.50(1H, 2br m), 3.08-2.68 (3H, br m), 2.37 (3H, s), 1.93-0.93 (10H, br m).

(b) N-Cyclohexyl-N-methyl-4-bromomethylbenzamide

Utilising the procedure described in Example 1(a) employingN-cyclohexyl-N-methyl-4-methylbenzamide in lieu of pltoluenesulphonylchloride -and tetrachloromethane as solvent yielded crudeN-cyclohexyl-N-methyl-4-bromomethylbenzamide (67%) as an orange waxysolid.

i.r. (CH₂ C! ₂) 2935, 1720 cm⁻¹

delta_(H) 7.46 (2H, d, J 8.1 Hz), 7.34 (2H, d, J 8.1 Hz), 4.51 (2H, s),3.78, 3.50 (1H, 2br m), 2.97 (3H, br s), 1.89-0.98 (10H, br m).

(c) N-CyclOhexyl-N-methyl-4-(1H-imidazo[4,5-c]pyridylmethyl)benzamide

Sodium bis (trimethylsilyl)amide (22 ml of 1 M solution in THF) wasadded to a stirred solution of imidazo[4,5-c]pyridine (2.60 g, 0.02 mol)in dry THF (200 ml) under argon. A fine white precipitate formed. After90 m the mixture was treated withN-cyclohexyl-N-methyl-4-bromomethylbenzamide (6.20 g, 0.02 mol)dissolved in dry THF (50 ml). The mixture was allowed to warm to ambienttemperature and stirred overnight. Methanol (1 ml) was added, followedby water and the product extracted using ethyl acetate (3×150 ml). Thecombined organic layers were washed with water (2×100 ml), dried overanhydrous potassium carbonate and the soilvent removed to give the crudeproduct. Flash chromatography (flash silica: 10% methanol in ethylacetate) followed by repeated fractional crystallisation (6 times fromethyl acetate/DIPE) gave the desired regioisomerN-cyclohexyl-N-methyl-4-(1H-imidazo[4, 5-c]pyridylmethyl)benzamide (0.39g, 5%) as an off white crystalline solid.

m.p. 121°-123° C.

Analysis calculated for C₂₁ H₂₄ N₄₀.0.6 H₂ O; Requires C 70.21, H 7.07,N 15.60; Found C 70.08, H 6.91N 15.37.

i.r. (KBr) 3080, 2930, 1615 cm⁻¹

delta_(H) 9.17 (1H, s), 8.42 (1H, d, J 5.6 Hz), 8.03 (1H, s), 7.37 (2H,d, J 7.8 Hz), 7.27-7.19 (3H, m), 5.42 (2H, s), 4.50, 3.37 (1H, 2br m),2.96, 2.76 (3H, 2br s), 2.05-1.02 (10H, br m).

Note on the Assignment of Regiochemistry

From a number of reactions used to prepare the exemplary compounds,⁼which possess the imidazo[4,5-c]pyridine and2-methylimidazo[4,5-c]pyridine moiety, two regioisomers are isolated;these regioisomers were usually separated by chromatography (silica gel:1-10% methanol in DCM). The first regioisomer to elute is the3H-imidazo[4,5-c]pyridyl or 3H-2-methylimidazo[4,5-c]pyridyl derivativeand has been denoted as regioisomer (A) and the second to elute is the1H-imidazo[4,5-c]pyridyl or 1H-2-methylimidazo[4,5-c]pyridyl derivativeand has been denoted as being regioisomer (B). The assignment ofregiochemisitry is based upon a differential n.O.e. NMR experimentconducted at 500 MHz on Example 35 regioisomer (B). Irradiation of thebenzylic protons (delta 5.39 ppm) showed enhancements to the2-methylimidazopyridine H-7 doublet signal (9%) and methyl protons (2%)and to the phenyl meta protons (8%). The regioisomers of the otherExamples have been assigned by comparison of their ¹ H NMR spectra withthat of Example 35 regioisomers (A) and (B).

Pharmacology Example 1

The inhibition of 3H-PAF binding no human platelet plasma membrane bycompounds of general formula I was determined by isotopic labelling andfiltration techniques. .Platelet concentrates were obtained from ahospital blood bank. These platelet concentrates (500-2500 ml.) werecentrifuged at 800 rpm for 10 minutes in a SORVALL RC₃ B centrifuge toremove the red blood cells present. (The word SORVALL is a trade mark.)The supernatant was subsequently centrifuged at 3,000 rpm in a SORVALLRC₃ B centrifuge to pellet the platelens present. The platelet richpellets were resuspended in a minimum volume of buffer (150 mM NaC₁, 10mM Tris, 2 mM EDTA, pH 7.5) and layered onto Ficoll-Paque gradients, 9ml platelet concentrate to 2 ml Ficoll, and centrifuged at 1,900 rpm for15 minutes in a SORVALL RT6000 centrifuge. This step removes theresidual red blood cells and other nonspecific material such aslymphocytes from the preparation. The platelets which form a bandbetween the plasma and the Ficoll were removed, resuspended in the abovebuffer and centrifuged at 3,000 rpm for 10 minutes in a SORVALL RT6000centrifuge. The pelleted platelets were resuspended in buffer (10 mMTris, 5 mM MgCl₂, 2 mM EDTA, pH 7.0), snap freezed in liquid N₂ andallowed to thaw slowly at room temperature in order to lyse theplatelets. The latter step was repeated at least 3 times to ensureproper lysis. The lysed platelets were centrifuged at 3,000 rpm for 10minutes in a SORVALL RT6000 centrifuge and resuspended in buffer. Thelatter step w&S repeated twice in order to remove any cytoplasmicproteins which may hydrolyse the platelet activating factor (PAF)receptor. The prepared platelet membranes may be stored at -70° C. Afterthawing the prepared membranes were centrifuged in a SORVALL RT6000 at3,000 rpm for 10 minutes and resuspended in assay buffer.

The assay was conducted by preparing a series of Tris-buffered solutionsof the selected antagonist of predetermined concentrations. Each ofthese solutions contained 3H-PAF (0.5 nM; 1-O-[³H]octadecyl-2-acetyl-sn-glycero-3-phosphoryl choline with a specificactivity of 132 Ci/mmol), unlabelled PAF (1000 nM), a known amount ofthe test antagonist, and a sufficient amount of

Tris-buffersolution (10 mM Tris, 5 mM MgCl₂, pH 7.0, 0.25% BSA) to makethe final volume lml. Incubation was initiated by the addition of 100 μgof the isolated membrane fraction to each of the above solutions at 0°C. Two control samples, one (C1) which contained all the ingredientsdescribed above except the antagonist and the other (C2) contains C1plus a 1000-fold excess of unlabelled PAF, were also prepared andincubated simultaneously with the tesit samples. After 1 hourincubation, each solution was filtered rapidly under vacuo through aWHATMAN GF/C glass fibre filter in order to separate unbound PAF frombound PAF. (The word WHATMAN is a trade mark.) The residue in each casewas rapidly washed 4 times with 5 ml cold (4° C.) Tris-buffer solution.Each washed residue was dried under vacuum on a sampling manifold andplaced into vials containing 20 ml of OPTIPHASE MP scintillation fluidand the radioactivity counted in a. liquid scintillation counter. (Theword OPTIPHASE is a trade mark.) Defining the counts for total bindingwith antagonist from a test sample as "TBA"; the counts for totalbinding from the control sample C1 as "TB"; and the counts fornonspecific binding from the control sample C2 as "NSB", the percentinhibition of each test antagonist can be determined by the followingequation:

    % Inhibition=[(TB-TBA)/SB]×100

where the specific binding SB=TB-NSB

Table 1 lists results from this assay for inhibition of ³ H-PAF receptorbinding for illustrative examples of the compounds of this invention.Also presented in Table 1 is the result for a comparative example(N-cyclohexyl-N-methyl-4 -(1H-imidazo[4,5c]pyridylmethyl) benzamide.This compound (a PAF antagonist described in EP-A-0260613) is not withinthe scope of the invention.

                  TABLE 1                                                         ______________________________________                                        Results for inhibition of .sup.3 H-PAF receptor binding                                      Inhibition of .sup.3 H-PAF binding                             Example        IC.sub.50 nM                                                   ______________________________________                                         6             30                                                              7             20                                                             14             15                                                             .sup. 32B      8                                                              .sup. 35B      0.2                                                            .sup.   42A    2                                                              .sup. 43B      1                                                              .sup. 53B      0.15                                                           54             3                                                              .sup. 57B      1                                                              Comparative Example                                                                          10,000                                                         ______________________________________                                    

Pharmacology Example 2

The activity of the compounds of general formula I is also demonstratedin vivo by their ability to reverse the hypotension caused by aninfusion of PAF in rats. Male Spmgue-Dawley rats (300-350 g) wereanaesthetised with a mixture of sodium pentobarbitOne, 22.5 mg/kg andthiopental 62.5 mg/kg. Through a midline incision in the neck, thetrachea was cannulated and the animals breathed spontaneously. A carotidartery was cannulated for the measurement of blood pressure and thissignal was used to trigger a rate meter to measure heart rate. BothJugular veins were cannulated: one for the infusion of PAF and the otherfor the bolus administration of test compounds.

PAF, 100 ng/kg/min was infused i.v. until a sustained fall in mean bloodpressure of 50 mmHg was achieved. Test compounds were administered i.v.as a bolus and resulted in a dose dependent reversal of the PAF inducedhypotension. The peak of this reversal was measured and the dose tocause a 50% reversal of the hypotensive PAF response (ED₅₀) calculatedby straight line interpolation and the results are presented in Table 2.Also presented in Table 2 is the result for a comparative example(N-cyclohexyl-N-methyl-4-(1H-imidazo[4,5-c]pyridylmethyl)benzamide. Thiscompound (a PAF antagonist described in EP-A-0260613) is not within thescope of the invention.

                  TABLE 2                                                         ______________________________________                                        Results for inhibition of PAF-induced                                         hypotension in the rat                                                        Example          ED.sub.50 (μg/kg i.v.)                                    ______________________________________                                         7               11.6                                                         12               21.0                                                         .sup. 32B        2.1                                                          .sup. 53B        0.5                                                          .sup. 56B        0.6                                                          Comparative Example                                                                            150                                                          ______________________________________                                    

Pharmacology Example 3

Rats were anaesthetised with a mixture of sodium pentobarbitone, 22.5mg/kg, and thiopental, 62.5 mg/kg. The animals breathed spontaneously,air enriched with oxygen, and a carotid artery was cannulated for themeasurement of blood pressure and heart rate. E. Coli acetone powderserotype No. 0111:B4 (endotoxin) 100 mg/kg, was administered via aJugular vein; this resulted in a hypotension of approximately 50 mmHgwhich was sustained for up to 2 hours. Test compounds were administeredi.v. via the other Jugular vein as a bolus.

The dose which resulted in a 50% reversal of the endotoxin inducedhypotension (ED₅₀) was calculated by straight line interpolation betweenthe mean responses, calculated from bracketing doses, giving one doseper compound per animal. The results are presented in Table 3.

                  TABLE 3                                                         ______________________________________                                        Results for inhibition of endotoxin induced                                   hypotension in the rat                                                        Example      ED.sub.50 (μg/kg i.v.)                                        ______________________________________                                        32B          15.5                                                             35B           2.9                                                             ______________________________________                                    

Pharmacology Example 4

The inhibition of PAF induced bronchoconstriction was measured inanaesthetised artificially ventilated guinea-pigs (450-500 g) using amodified version of the Konzett-Rossler technique (Konzett M and RosslerR, Naunym-Schmiedeb. Arch. Exp. Pathol. Pharmakol., 1940, 197, 71). MaleDunkin-Hartley guinea-pigs were anaesthetiSed with urethane, 1.6 g/kg.Through a midline neck incision, the trachea was cannulated and theanimal ventilated with a constant tidal volume set between 5 and 15 ml,to give a tracheal inflation pressure of 15 mmHg at a rate of 40 perminute. Acarotid artery was cannulated for the measurement of bloodpresssure and heart rate and both jugular veins were cannulated, one forthe infusion of PAF and the other for the administration of testcompounds. PAF, 40 ng/kg/min in saline with 0.25% ibovine serum albumin,was infused i.v. to produced a 100% increase in tracheal inflationpressure, and bronchoconstrictor effects were determined. Test compoundswere administered p.o. (10 mg/kg) 1 hour before the infusion of PAF wasstarted whilst the animals were conscious. The percentage inhibition ofPAF-induced bronchoconstriction (ED50) was determined and the resultsare presented in Table 4.

                  TABLE 4                                                         ______________________________________                                        Results for inhibition of PAF-induced                                         Bronchoconstriction in the guinea pig                                         Example    % Inhibition (10 mg/kg p.o.)                                       ______________________________________                                        53(B)      91                                                                 56(B)      72                                                                 60(B)      60                                                                 69(B)      60                                                                 ______________________________________                                    

We claim:
 1. A compound of formula I; ##STR101## wherein: A¹ is ═N--,═CH-- or ═CR¹ --,A² is --N═, --CH═ or --CR² ═;provided that, when one ofA¹ and A² is a nitrogen atom, the other of A¹ and A² is other than anitrogen atom; R represents hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl,halogen or --OC₁ -C₆ alkyl; each of R¹ and R² independently representshydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, halogen, --CN, --CO₂ H,--CO₂ C₁ -C₆ alkyl, --CONH₂, --CHO, --CH₂ OH, --CF₃, --OC₁ -DC₆ alkyl,--SC₁ -C₆ alkyl, --SOC₁ -C₆ alkyl, --SO₂ C₁ -C₆ alkyl, --NH₂, --NHCOMeor --NO₂, or R¹ and R² together with the carbon atoms to which they areattached form a fused phenyl ring; R³ represents hydrogen, --C₁ -C₆alkhyl, --C₂ -c₆ alkenyl, --C₂ -C₆ alkynyl, --OC₁ -C₆ alkyl, --SC₁ -C₆alkyl, --(C₁ -C₆ alkyl)OC₁ -C₆ alkyl, --CF₃, --(C₁ -C₆ alkyl)phenyl,--C₃ -C₈ cycloalkyl, --C₄ -C₈ cycloalkcnyl, --(C₁ -C₆ alkyl)C₃ -C₈cycloalkyl, --(C₁ -C₆ alkyl)C₄ -C₈ cycloalkenyl or thiophenyl; R⁴represents hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, --C₂ -C₆ alkynyl,--CO₂ C₁ -C₆ alkyl, --SC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)SC₁ -C₆ alkyl,--(C₁ -C₆ alkyl)OC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)phcnyl or thiophenyl; R⁵represents hydrogen, --C₁ -C₆ alkyl, --C_(2C) ₆ alkenyl, --C₂ -C₆alkynyl, --COC₁ -C₆ alkyl, --CO₂ C₁ -C₆ alkyl, --(COC₁ -C₆ alkyl)phenyl,--(CO₂ -C₁ -C₆ alkyl)phenyl, --(C₁ -C₆ alkyl)OC₁ -C₆ alkyl, --(C₁ -C₆alkyl)SC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl, --C₃ -C₈cycloalkyl, --C₄ -C₈ cycloalkenyl or a group --D wherein D represents agroup: ##STR102## wherein n is an integer from 0 to 3, and each of R⁸,and R⁹ is independently hydrogen, --C₁ -C₆ alkyl, --C₂ -C₆ alkenyl, --C₂-C₆ alkynyl, halogen, --CN, --CO₂ H, --CO₂ C₁ -C₆ alkyl, --CONH₂, CONHC₁-C₆ alkyl, --CONH(C₁ -C₆ alkyl)₂, --COH, --CH₂ OH, --CF₃, --OC₁ -C₆alkyl, --SC₁ -C₆ alkyl, --SOC₁ -C₆ alkyl, or --SO₂ C₁ -C₆ alkyl, --NH₂or --NHCOMe; each of R⁶ and R⁷ independently represents hydrogen,halogen, --C₁ C₆ alkyl optionally substituted by one or more halogenatoms, --C₂ -C₆ alkenyl, --C₂ -C₆ alkynyl, --(C₁ -C₆ alkyl)CO₂ C₁ -C₆alkyl, --(C₁ -C₆ alkyl)SC₁ -C₆ alkyl, --(C₁ -C₆ alkyl)OC₁ -C₆ alkyl,--(C₁ -C₆ alkyl)N(C₁ -C₆ alkyl)₂, C₃ -C₈ cycloalkyl, --C₄ -C₈cycloalkenyl, --(C₁ -C₆ alkyl)C₃ -C₆ alkyl)C₃ -C₈ cycloalkyl, --(C₁ -C₆alkyl)C₄ -C₈ cycloalkenyl, --(C₁ -C₆ alkyl)OC₃ -C₈ cycloalkyl, --(C₁ -C₆alkyl)OC₄ -C₈ cycloalkenyl, --(C₁ -C₆ alkyl)SC₃ -C₈ cycloalkyl, --(C₁-C.sub. 6 alkyl)SC₄ -C₈ cycloalkenyl, a side chain of a naturallyoccurring amino acid, a group -D as defined above or a --(C₁ -C₆alkyl)OD group wherein D is as defined above; or R⁶ together with R⁵ andthe atoms to which they are attached form a 5 to 8 memberednitrogen-containing heterocyclic ring; or R⁶ and R⁷ together with thecarbon atom to which they are attached form a C₃ -C₈ cycloalkyl ring; Brepresents CO₂ H and salts thereof.
 2. A compound as claimed in claim 1,wherein R represents a halogen atom or a hydrogen atom.
 3. A compound asclaimed in claim 2, wherein R¹ represents a halogen atom or a hydrogenatom.
 4. A compound as claimed in claim 3, wherein R² represents halogenatom or a hydrogen atom.
 5. A compound as claimed in claim 4, wherein R³represents a hydrogen atom or a --C₁ -C₆ alkyl group.
 6. A compound asclaimed in claim 5, wherein R⁴ represents a hydrogen atom.
 7. A compoundas claimed in claim 6, wherein R⁵ represents a hydrogen atom, a --C₁ -C₆alkyl group, a --C₂ -C₆ alkenyl group, a --(COC₁ -C₆ alkyl group, a--CO₂ C₁ -C₆ alkyl group or a --(C₁ -C₆ alkyl)CO₂ C₁ -C₆ alkyl group. 8.A compound as claimed in claim 7, wherein R⁶ represents a hydrogen atom,a --C₁ -C₆ alkyl group, a --C₂ -C₆ alkenyl group, a --(C1-C₆ alkyl) CO₂C₁ -C₆ alkyl group, --(C₁ -C₆ alkyl) SC₁ -C₆ alkyl group, a side chainof a naturally occurring amino acid, a group D or a --(C₁ -C₆ alkyl)ODgroup, or R⁵ and R⁶, and the atoms to which they are attached form a 5to 8 membered nitrogen-containing heterocyclic ring.
 9. A compiund asclaimed in claim 8, wherein R⁷ represents a hydrogen atom, a --C₁ -C₆alkyl group or together with R⁶ and the carbon atom to which they areattached forms a C₃ -C₈ cycloalkyl ring.
 10. A compound as claimed inclaim 9, wherein, R⁶ represents the side chain of a naturally occurringamino acid, the stereochemistry of the carbon to which R⁶ and R⁷ areattached is the same as that of the naturally occurring amino acid. 11.A compound as claimed in claim 10, wherein n represents an integer of 0or
 1. 12. A compound as claimed in claim 11, wherein R⁸ represents ahydrogen atom or a --C₁ -C₆ alkyl group.
 13. A compound as claimed inclaim 12, wherein R⁹ represents a hydrogen atom.
 14. A comund accordingto claim 1 which isN-methyl-N-4-(1H-2-methylimidazo(4,5-c)pyridinylmethyl)phenylsulphonyl-L-leucine.